PIC Spectrum Analysis DSP

Schematic

Steve Thackery says:

[Microchip Application Note AN542 doesn't work]

*No* disrespect to the guys who wrote it, but it doesn't work.

Over the last several months I've been developing a product for my employer which uses a fast fourier transform as part of its functionality. The product is based upon a 17C44, by the way.

I was foolish enough to plan my timescales assuming that the Microchip FFT would be pretty well "plug and play". After all, I do tend to trust the stuff they publish. How wrong I was!

I won't bore you with the details, but Microchip's FFT is seriously defective. I can only guess that it didn't receive much testing. In fact, reading between the lines in AN542 it becomes clear that it was primarily written as a *benchmarking* exercise rather than a reliable FFT module for use in our projects.

Basically, if you test it with the waveform shown in the AN, it works perfectly. I should have been suspicous, even so. The waveform shown is of very low frequency, and has a whole number of cycles in the sampling window. Alter that frequency by even a small amount, so that there isn't a whole number of cycles in the window and the whole thing goes haywire! It generates artefacts in the FFT output all over the place, both above and below the "real" frequency. Similarly, test it at higher frequencies with sine or square waves, and you get a complete spectrum of rubbish at the output.

Incidentally, it wasn't made clear in the AN that permissible input range of values is between 0 and 3FFF. In other words, you need to DC-shift your sound sample so its centred around 1FFF, and adjust its gain. That caught us out for a couple of days!

We assumed it must be something we were doing wrong and spent ages poring over the AN to see if we were doing something stupid. We also tried working through the code itself, but it is almost inpenetrable. We tried everything, including using very small amplitude signals, but to no avail. The output is rubbish *except* with very low frequency square waves with a whole number of cycles in the window.

I can only imagine that there is a scaling problem somewhere in the maths. It looks like there is some sort of overflow or fold-back going on.

This cost me two months of development time and made me very unpopular with my employer and customer!

In the end we gave up and looked elsewhere. This is where Robert Lacoste comes into the picture. He developed his own FFT module from scratch and incorporated it into his PIC'Spectrum product. I contacted him and asked if he would be willing to let us use his FFT module - for prototyping and test purposes only - in our own product. He was willing and incredibly helpful, answering all our questions with clarity.

It took us two days to unplug the Microchip FFT module and plug in the Lacoste module. Here's what happened. It worked PERFECTLY! The output is classic, text-book perfect under all circumstances. Furthermore, it runs at least ten times as fast as the Microchip module.

Let me state publicly my most grateful thanks to Robert. If you need to include an FFT in any of your products, contact him on robert_lacoste@yahoo.fr He allowed us free use in our prototypes, and suggested a very reasonable royalty on our production models. I expect he might extend a similar deal to others.

In summary, then: BEWARE the Microchip FFT, and THANK YOU Robert Lacoste!

See also:

;============================================================================
; PROJECT     : PIC'SPECTRUM
;
; FILE        : PICSPECT.ASM
;
; VERSION     : 1.0
;
; DESCRIPTION :
;
; PIC'SCOPE digital audio spectrum analyser - Main source file
;
; This project is a complete audio spectrum analyser with output on a
; standard VGA display, done entirely with a PIC17C756 microcontroler.
;
; The controler is in charge of :
; - ADC acquisition of the incoming signal
; - Fast Fourier Transform of the signal
; - Power calculation and if required logarithmic scaling
; - Video generation entirely in software
; of course in real time.
;
; Developped on MICROCHIP's MPLAB 3.31.0
; To be embedded in a PIC17C756 (32MHz crystal)
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================


;----------------------------------------------------------------------------
; System definitions
;----------------------------------------------------------------------------

		PROCESSOR  17C756	; Assembler directives
		RADIX 	   HEX
		ERRORLEVEL 0
		ERRORLEVEL -302		; no bank control warnings

		TITLE 	   "PIC'SPECTRUM"
		SUBTITLE   "(C) Robert Lacoste"
		
#include	"P17C756.INC"		; Processor dependant declarations

		; config register :
		; XT osc, no watchdog, brown-out reset active, microcontroler
		__CONFIG (_XT_OSC & _WDT_OFF & _BODEN_ON & _MC_MODE)


;----------------------------------------------------------------------------
; Application constants
;----------------------------------------------------------------------------

MAXPIXVAL	equ D'127'		; maximum scaled pixel value

INITTIM		equ H'FFFF'-D'254'+D'13'+D'5'; timer load value,
					; 254 because 31.77µS=254*4/32MHz
					; minus 13 for irq to reload delay
					; minus 5 for timer to irq delay

BKG_COLOR	equ B'00000100'		; background=Blue
SLINE_COLOR	equ B'00000011'		; separation lines=Yellow
SHORTS_COLOR	equ B'00000011'		; small scale indicator=Yellow
LONGS_COLOR	equ B'00000011'		; long scale indicator=Yellow
FREQ_COLOR	equ B'00000001'		; Frequency bars=Red
BKGTITLE_COLOR	equ B'00000010'		; Background title=Green
TITLE_COLOR	equ B'00000000'		; Title=Black
HOLD_COLOR	equ B'00000001'		; Hold=Red


;----------------------------------------------------------------------------
; Vectors
;----------------------------------------------------------------------------

reset_vector	org H'0000'
		goto start		; Initialisation

intpin_vector	org H'0008'
		goto start		; should not occur

timer0_vector	org H'0010'
		goto it_timer		; horizontal sync interrupt

t0cki_vector	org H'0018'
		goto start		; should not occur

periph_vector	org H'0020'
		goto start		; should not occur
 
start_appl	org H'0050'		; start of application area

		
;----------------------------------------------------------------------------
; Inclusion of extern application files
;----------------------------------------------------------------------------

#include 	"vars.inc"		; Variables declarations
#include	"fixed.inc"		; Fixed point arithmetic
#include	"testsig.inc"		; Test signals generation
#include	"fft.inc"		; FFT calculation routines
#include	"powers.inc"		; power calculation & display access
#include	"irq.inc"		; interrupt routine & video generation


;----------------------------------------------------------------------------
; Main starting point
;----------------------------------------------------------------------------

start		nop
		BANKSEL zone_main

;--> Initialisation

		call initialize		; initialization of ports & variables
		call realfft		; do the first FFT (on the test signal)
		call init_timer		; launch timer0 interrupts
	
mainloop	nop

;--> Power spectrum calculation & scaling

		movlb 0			; if RB7=0 (mode log),
		btfsc PORTB,7
		goto spectlin
spectlog	call powerlog		; calculate spectrum in log scale
		goto main1
spectlin	call powerlin		; else calculate spectrum in lin scale

main1		nop

;--> Analog acquisition

		movlb 0			; if RB6=1 (non hold mode),
		btfss PORTB,6		; do analog sample acquisition :
		goto main2
		movlb 1			; RD1=1 (debug line : ADC going on)
		bsf PORTD,1
		BANKSEL num_sample	; sample number=0
		clrf num_sample,F
		call init_adc		; initialize analog acquisition
		BANKSEL acq_request
		movlw 1			; put acqrequest flag to 1
		movwf acq_request

		clrf WREG,F		; and wait for it to be 0
acqwait		cpfseq acq_request
		goto acqwait

		movlb 1			; RD1=0 (debug line : ADC going on)
		bcf PORTD,1

;--> Do the FFT

		movlb 1			; RD0=1 (debug line : FFT going on)
		bsf PORTD,0

		BANKSEL zone_main
		call realfft		; do the FFT

		movlb 1			; RD0=0 (debug line : FFT going on)
		bcf PORTD,0

;--> And loop !
		
main2		goto mainloop


;----------------------------------------------------------------------------
; Ports & variables initialization
;----------------------------------------------------------------------------

initialize	nop

;--> Variables initialization

		BANKSEL acq_request	; reset adc control registers
		clrf acq_request,F
		clrf num_sample,F

		BANKSEL scan_line	; reset scan line number
		clrf scan_line,F	; (will be incremented to 1 at the
		clrf scan_line+1,F	; first interrupt)

		BANKSEL displ0		; reset displ0 buffer
		movlw low displ0
		movwf FSR0
		bcf ALUSTA,FS1		; auto increment mode
		bsf ALUSTA,FS0
		bcf ALUSTA,C
		movlw low displ0+D'64'
rstdispl0	clrf INDF0,F
		cpfseq FSR0
		goto rstdispl0

		BANKSEL displ1		; reset displ1 buffer
		movlw low displ1
		movwf FSR0
		bcf ALUSTA,FS1		; auto increment mode
		bsf ALUSTA,FS0
		bcf ALUSTA,C
		movlw low displ0+D'64'
rstdispl1	clrf INDF0,F
		cpfseq FSR0
		goto rstdispl1

		bsf ALUSTA,FS1		; return to non-increment mode

		BANKSEL zone_main
		m_ldaconst H'2000'	; generate test square signal
		movlw D'16'
		call test_square

;--> Ports initialization

		movlw B'11111000'	; RB0 to RB2 are outputs
		movlb 0
		movwf DDRB
		clrf PORTB,F		; initialized to 0

		movlw B'10101111'	; RC4 and RC6 are outputs
		movlb 1
		movwf DDRC
		bcf PORTC,4		; RC4=0 (Hsync)
		bsf PORTC,6		; RC6=1 (Vsync)

		movlw B'11111000'	; RD0 to RD2 are outputs
		movlb 1
		movwf DDRD
		clrf PORTD,F		; initialized to 0

		movlw B'01111111'	; RG7 is output
		movlb 5
		movwf DDRG
		clrf PORTG,F		; initialized to 0

		return


;----------------------------------------------------------------------------
; Initialization of timer0
; 
; Generate an interrupt every 31.77 micro-second (horizontal refresh
; rate for VGA display in 640x350 mode = 31.476KHz)
;
; Warning : interrupts will start immediatly after calling this routine
;----------------------------------------------------------------------------

init_timer	nop

		bsf CPUSTA,GLINTD	; disable global interrupts

		bsf T0STA,T0CS		; select internal clock
		bcf T0STA,T0PS3		; and prescale factor 1:1
		bcf T0STA,T0PS2
		bcf T0STA,T0PS1
		bcf T0STA,T0PS0

		BANKSEL tmpcpt
		movlw high INITTIM	; load timer
		movwf tmpcpt
		movlw low INITTIM
		movwf TMR0L
		movfp tmpcpt,TMR0H
 
		bcf INTSTA,PEIE		; disable PEI interrupts
		bcf INTSTA,T0CKIE	; disable external interrupts on RA1
		bcf INTSTA,INTE		; disable external interrupts on RA0

		bsf INTSTA,T0IE		; enable timer0 interrupts

		bcf CPUSTA,GLINTD	; enable global interrupts

		return


;----------------------------------------------------------------------------
; Configuration of analog acquisition port
;
; Connect the analog source and configure the A/D sub-system. Acquisition
; will be done by the interrupt routine synchronously with video generation. 
;----------------------------------------------------------------------------

init_adc	movlb 5
		movlw B'10000000'	; clock=F/64 (2µS conversion),
		movwf ADCON1		; left justified, ref 0/5V

		movlw B'10000000'	; select chanel AD8
		movwf ADCON0

		bsf ADCON0,ADON		; switch on ADC sub-system

		return



		END

;============================================================================
;                             - END OF FILE -
;============================================================================
;============================================================================
; PROJECT     : UPS'SPECTRUM
;
; FILE        : VARS.INC
;
; VERSION     : 1.0
;
; DESCRIPTION : 
;
; Definition of all RAM variables, bank per bank. 
; Usage of each variable (used by main program, by interrupt routine or 
; both) is defined
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================


;----------------------------------------------------------------------------
; Unbanked RAM
;----------------------------------------------------------------------------

; unbanked RAM $1A to $1A : private unbanked save location for interrupt 
; routine. Other locations are in bank 0.

		cblock H'001A'
			sv_bsr		; BSR save location
		endc

; unbanked ram $1B to $1F : arithmetic working registers, to be used only
; by the main program

		cblock H'001B'		; arithmetic working registers 
			ra:2		; (format s-2-13)
			rb:2		; (format s-2-13)
			rdiv:1		; (8 bit unsigned int)
		endc


;----------------------------------------------------------------------------
; Bank 0
;----------------------------------------------------------------------------

; $20 to $7F : private registers for the interrupt routine
;	       and exchange registers & flags between main pgr and interrupt

		cblock H'0020'
			zone_irq:0
		endc

		cblock
			scan_line:2	; scan line number, from 1 to 449, H-L
			frame_num:1	; frame number (for blinkings)
			tmpcolor:1	; temporary storage of color
			tmpi:2		; temporary variable 
			tmpi2:2		; temporary variable
		endc

		cblock
			sv_alusta	; save location for registers
			sv_wreg		; during interrupt
			sv_fsr0	
		endc

		; WARNING : only these 4 registers (with bsr, saved in
		; non-banked ram) are automaticaly saved. Be carefull when
		; using FSR1 or table read registers !

		; Exchange registers et flags between main pgr and interrupt

		cblock
			acq_request:1	; Analog acquisition flag
					; (0:finished, 1:sampling, 2:convert)
			num_sample:1	; Analog sample number
		endc

; $80 to $FF : FFT data buffer 0...63 (2 bytes/value, big endian : H-L)

		cblock H'0080'
			data0:128	; (format s-2-13)
		endc

;----------------------------------------------------------------------------
; Bank 1
;----------------------------------------------------------------------------

; $20 to $7F : private registers for the main program

		cblock H'0120'	
			zone_main:0
		endc

		cblock			; temporary variables for FFT and
					; powers
			wr:2		; (format s-2-13)
			wpr:2		; (format s-2-13)
			wi:2		; (format s-2-13)
			wpi:2		; (format s-2-13)
			theta:2		; (format s-2-13)
			mmax:1		; counter
			m:1		; counter
			j:1		; counter
			istep:1		; counter
			i:1		; counter
			i1:1		; counter
			i2:1		; counter
			i3:1		; counter
			i4:1		; counter
		endc

		cblock			; temporary arithm. variables
			h1r:2		; (format s-2-13)
			h1i:2		; (format s-2-13)
			h2r:2		; (format s-2-13)
			h2i:2		; (format s-2-13)
			wtemp:2		; (format s-2-13)
		endc
			
		cblock			; generic counters
			cptm:2		; (16 bit unsigned int)
			cpti:2		; (16 bit unsigned int)
			cptj:2		; (16 bit unsigned int)
		endc

		cblock			; temporary registers for math.inc
			mres3:1		; for m_mult and m_divi
			mres2:1
			mres1:1
			mres0:1
			msign:1
			x0:2		; for m_sin
			x1:2
			x2:2
			sin_saveb:2
			scaletmp:2	; for m_scalelin and m_scalelog
			logresult:2	; for m_scalelog		
		endc

		cblock			; temporary registers for testsig.inc
			test_halfp:1
			test_step:2
			test_cval:2
		endc

		cblock
			tmpcpt:1	; temporary register for inittimer
		endc

; $80 to $FF : FFT data buffer 64...127 (2 bytes/value, big endian : H-L)

		cblock H'0180'
			data1:128	; (format s-2-13)
		endc

;----------------------------------------------------------------------------
; Bank 2
;----------------------------------------------------------------------------

; $20 to $5F : Display buffer 0...63

		cblock H'0220'
			displ0:64	; (value 0..MAXPIXVAL)
		endc

; $60 to $7F : unused

; $80 to $FF : FFT data buffer 128...191 (2 bytes/value, big endian : H-L)

		cblock H'0280'
			data2:128	; (format s-2-13)
		endc

;----------------------------------------------------------------------------
; Bank 3
;----------------------------------------------------------------------------

; $20 to $5F : Display buffer 64...127

		cblock H'0320'
			displ1:64	; (value 0..MAXPIXVAL)
		endc

; $60 to $7F : unused

; $80 to $FF : FFT data buffer 192...255 (2 bytes/value, big endian : H-L)

		cblock H'0380'
			data3:128	; (format s-2-13)
		endc


;============================================================================
;                             - END OF FILE -
;============================================================================
;============================================================================
; PROJECT     : PIC'SPECTRUM
;
; FILE        : FIXED.INC
;
; VERSION     : 1.0
;
; DESCRIPTION :
;
; Fixed point math routines, using a s-2-13 format (sign bit in 2-complement,
; 2 bits for the integer part, 13 bits for the decimal part).
;
; So values ranging +/-3.99999, resolution 1/2 exp 13 = 0.000122
;
; All functions and macros operate on registers ra,rb and rdiv. 
; Storage could be in a generic "arithmetic" register (2 bytes) or in the
; FFT data storage table ("data")
;
; The FFT data table ("data") is a 4x64 word (2 bytes) array, each of the
; four blocks being at at fixed adress ($80 to $ff) in the 4 banks.
;
; WARNING : ra/rb/rdiv are supposed to be in unbanked memory. Bank selector
; must be zone_main on input (access to arithmetic tempory registers) and is
; garanteed to be zone_main on exit
;
; In general, WREG is scrambled
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================


;----------------------------------------------------------------------------
; m_lda : 	copy a given general register (2 bytes) in register A
;----------------------------------------------------------------------------

m_lda		macro inreg
		movfp inreg,WREG
		movwf ra
		movfp inreg+1,WREG
		movwf ra+1
		endm

;----------------------------------------------------------------------------
; m_ldai :	get the data value pointed by reg and store it in A
;----------------------------------------------------------------------------

m_ldai		macro indexreg
		movfp indexreg, WREG
		movlr 0			; start with bank 0
		btfsc WREG,7		; select the good bank
		bsf BSR,5
		btfsc WREG,6		; based on 2 first bits of WREG
		bsf BSR,4
		bcf ALUSTA,C		; multiply by 2
		rlcf WREG,1
		bsf WREG,7		; and set high bit (data start at $80)
		movwf FSR0		; and use it as an index
		movpf INDF0,ra		; to get msb value
		incf FSR0,1
		movpf INDF0,ra+1	; and lsb value
		BANKSEL zone_main	; reset bank register
		endm
		
;----------------------------------------------------------------------------
; m_ldb : 	copy a given general register (2 bytes) in register B 
;----------------------------------------------------------------------------

m_ldb		macro inreg
		movfp inreg,WREG
		movwf rb
		movfp inreg+1,WREG
		movwf rb+1
		endm

;----------------------------------------------------------------------------
; m_ldbi :	get the data value pointed by reg and store it in B 
;----------------------------------------------------------------------------

m_ldbi		macro indexreg
		movfp indexreg,WREG
		movlr 0			; start with bank 0
		btfsc WREG,7		; select the good bank
		bsf BSR,5
		btfsc WREG,6		; based on 2 first bits of WREG
		bsf BSR,4
		bcf ALUSTA,C		; multiply by 2
		rlcf WREG,1
		bsf WREG,7		; and set high bit (data start at $80)
		movwf FSR0		; and use it as an index
		movpf INDF0,rb		; to get msb value
		incf FSR0,1
		movpf INDF0,rb+1	; and lsb value
		BANKSEL zone_main	; reset bank register
		endm

;----------------------------------------------------------------------------
; m_lddiv :	copy a given register (int, 1 byte) in register DIV
;----------------------------------------------------------------------------

m_lddiv		macro inreg
		movfp inreg,WREG
		movwf rdiv
		endm

;----------------------------------------------------------------------------
; m_sta :	store the value of A in a given general register (2 bytes)
;----------------------------------------------------------------------------

m_sta		macro outreg
		movfp ra,WREG
		movwf outreg
		movfp ra+1,WREG
		movwf outreg+1
		endm

;----------------------------------------------------------------------------
; m_stai :	store the value of A in the data value pointed by reg
;----------------------------------------------------------------------------

m_stai		macro indexreg
		movfp indexreg, WREG
		movlr 0			; start with bank 0
		btfsc WREG,7		; select the good bank
		bsf BSR,5
		btfsc WREG,6		; based on 2 first bits of WREG
		bsf BSR,4
		bcf ALUSTA,C		; multiply by 2
		rlcf WREG,1
		bsf WREG,7		; and set high bit (data start at $80)
		movwf FSR0		; and use it as an index
		movfp ra,INDF0		; to store msb value
		incf FSR0,1
		movfp ra+1,INDF0	; and lsb value
		BANKSEL zone_main	; reset bank register
		endm

;----------------------------------------------------------------------------
; m_ldaconst :	load an immediate value in A
;----------------------------------------------------------------------------

m_ldaconst	macro immvalue
		movlw high immvalue
		movwf ra
		movlw low  immvalue
		movwf ra+1
		endm
		
;----------------------------------------------------------------------------
; m_mvba :	copy B to A
;----------------------------------------------------------------------------

m_mvba		macro
		movfp rb,WREG
		movwf ra
		movfp rb+1,WREG
		movwf ra+1
		endm

;----------------------------------------------------------------------------
; m_mvab :	copy A to B
;----------------------------------------------------------------------------

m_mvab		macro
		movfp ra,WREG
		movwf rb
		movfp ra+1,WREG
		movwf rb+1
		endm

;----------------------------------------------------------------------------
; m_add :	add B to A (A=A+B)
;----------------------------------------------------------------------------

m_add		macro
		movfp rb+1,WREG		; low byte first
		addwf ra+1,1
		movfp rb,WREG		; and high byte with carry
		addwfc ra,1
		endm

;----------------------------------------------------------------------------
; m_sub :	substract B to A (A=A-B)
;----------------------------------------------------------------------------

m_sub		macro
		movfp rb+1,WREG		; low byte first
		subwf ra+1,1
		movfp rb,WREG		; and high byte with borrow
		subwfb ra,1
		endm

;----------------------------------------------------------------------------
; m_mult :	multiply A to B (A=A*B)
;		Warning : overflow not detected if result>4
;----------------------------------------------------------------------------

m_mult		movfp ra+1,WREG		; low byte x low byte
		mulwf rb+1
		movpf PRODH,mres1
		movpf PRODL,mres0
		movfp ra,WREG		; high byte x high byte
		mulwf rb
		movpf PRODH,mres3
		movpf PRODL,mres2
		movfp ra+1,WREG		; low byte x high byte
		mulwf rb
		movfp PRODL,WREG
		addwf mres1,F
		movfp PRODH,WREG
		addwfc mres2,F
		clrf WREG,F
		addwfc mres3,F
		movfp ra,WREG		; high byte x low byte
		mulwf rb+1
		movfp PRODL,WREG
		addwf mres1,F
		movfp PRODH,WREG
		addwfc mres2,F
		clrf WREG,F
		addwfc mres3,F
		btfss rb,7		; test if B<0
		goto sign_ra
		movfp ra+1,WREG		; if so, adjust value
		subwf mres2,F
		movfp ra,WREG
		subwfb mres3,F
sign_ra		btfss ra,7		; test if A<0
		goto sign_end
		movfp rb+1,WREG		; if so, adjust value
		subwf mres2,F
		movfp rb,WREG
		subwfb mres3,F
sign_end	rlcf mres1,F		; shift left one time
		rlcf mres2,F
		rlcf mres3,F
		rlcf mres1,F		; shift left one time
		rlcf mres2,F
		rlcf mres3,F
		rlcf mres1,F		; shift left one time
		rlcf mres2,F
		rlcf mres3,F
		movfp mres3, ra		; forget mres1 and store result
		movfp mres2, ra+1	; in register A
end_mult	return

;----------------------------------------------------------------------------
; m_divi :	divide A with rdiv (A=A/DIV), rdiv being a non signed integer 
;		value and not a fixed decimal value
;
; call routines provided in Microchip's application notes (see div.inc)
;----------------------------------------------------------------------------

; Correspondances between AN617 variables and pic'spectrum's...
#define		AARGB0 (ra)
#define		AARGB1 (ra+1)
#define		ACCB0  (ra)
#define		ACCB1  (ra+1)
#define 	BARGB0 (rdiv)
#define		REMB0  (mres0)
#define		TEMP   (mres1)

#include	"div.inc"		; include 16/8 unsigned routine
					; from microchip's application
					; note AN617

m_divi		bcf msign,0
		btfss ra,7		; save sign of A
		goto m_divdiv
		bsf msign,0

		comf ra,F		; if A<0, A=-A
		comf ra+1,F
		movlw 1
		addwf ra+1,F
		movlw 0
		addwfc ra,F

m_divdiv	call FXD1608U		; do the division

		btfss msign,0		; if A was <0
		goto end_mdivi
		comf ra,F		; A=-A
		comf ra+1,F
		movlw 1
		addwf ra+1,F
		movlw 0
		addwfc ra,F

end_mdivi	return


;----------------------------------------------------------------------------
; m_div2 :	divide A with 2 (A=A/2)
;----------------------------------------------------------------------------

m_div2		macro
		bcf ALUSTA,C
		rrcf ra,1		; divide high byte
		rrcf ra+1,1		; and low byte
		btfsc ra,6		; test old sign bit
		bsf ra,7		; if set, report it to msb
		endm

;----------------------------------------------------------------------------
; m_sin :	replace A with sin(A)
;
; Sinus calculated by interpolation of tables values got with the MSB of A 
; (v_msb and v_msb+1 are the table values corresponding for msb A and the next
; one in the table, with rollover on 0)
;
; ra=(((v_msb+1)*lsb ra+(v_msb)*(1-lsb ra));
;
;----------------------------------------------------------------------------

		radix dec
sintable	dw 0
		dw   255,   511,   766,  1021,  1274,  1527,  1777,  2026
		dw  2273,  2518,  2760,  3000,  3237,  3470,  3700,  3927
		dw  4150,  4368,  4583,  4793,  4998,  5198,  5393,  5583
		dw  5768,  5947,  6120,  6287,  6448,  6603,  6751,  6893
		dw  7028,  7156,  7277,  7391,  7498,  7597,  7689,  7774
		dw  7850,  7920,  7981,  8035,  8081,  8119,  8149,  8171
		dw  8185,  8191,  8189,  8179,  8162,  8136,  8102,  8060
		dw  8011,  7953,  7888,  7815,  7735,  7647,  7551,  7448
		dw  7338,  7221,  7097,  6965,  6827,  6682,  6531,  6373
		dw  6210,  6040,  5864,  5682,  5495,  5303,  5105,  4902
		dw  4695,  4483,  4266,  4046,  3821,  3593,  3361,  3126
		dw  2888,  2647,  2404,  2158,  1910,  1660,  1408,  1156
		dw   902,   647,   391,   135,  -120,  -375,  -631,  -886
		dw -1140, -1393, -1644, -1894, -2142, -2388, -2632, -2873
		dw -3111, -3347, -3579, -3807, -4032, -4253, -4469, -4682
		dw -4889, -5092, -5290, -5483, -5671, -5853, -6029,  6199
		dw  6029,  5853,  5671,  5483,  5290,  5092,  4889,  4682
		dw  4469,  4253,  4032,  3807,  3579,  3347,  3111,  2873
		dw  2632,  2388,  2142,  1894,  1644,  1393,  1140,   886
		dw   631,   375,   120,  -135,  -391,  -647,  -902, -1156
		dw -1408, -1660, -1910, -2158, -2404, -2647, -2888, -3126
		dw -3361, -3593, -3821, -4046, -4266, -4483, -4695, -4902
		dw -5105, -5303, -5495, -5682, -5864, -6040, -6210, -6373
		dw -6531, -6682, -6827, -6965, -7097, -7221, -7338, -7448
		dw -7551, -7647, -7735, -7815, -7888, -7953, -8011, -8060
		dw -8102, -8136, -8162, -8179, -8189, -8191, -8185, -8171
		dw -8149, -8119, -8081, -8035, -7981, -7920, -7850, -7774
		dw -7689, -7597, -7498, -7391, -7277, -7156, -7028, -6893
		dw -6751, -6603, -6448, -6287, -6120, -5947, -5768, -5583
		dw -5393, -5198, -4998, -4793, -4583, -4368, -4150, -3927
		dw -3700, -3470, -3237, -3000, -2760, -2518, -2273, -2026
		dw -1777, -1527, -1274, -1021,  -766,  -511,  -255		
		radix hex


m_sin		movpf rb,sin_saveb	; save B register
		movpf rb+1,sin_saveb+1
		clrf x0+1,F
		movlw low (sintable)	; get table value corresponding 
		addwf ra,W		; to the MSB of A -> x0
		movwf TBLPTRL
		movlw high (sintable)
		addwfc x0+1,W
		movwf TBLPTRH
		tablrd 0,0,x0+1		; dummy read, update TABLATH
		tlrd 1,x0		; read high byte
		tablrd 0,1,x0+1		; and low byte.

		clrf x1+1,F
		movfp ra,WREG		; get table value corresponding 
		incf WREG,W		; to the MSB of A+1, with rollover at 0
		addlw low (sintable)	; -> x1
		movwf TBLPTRL
		movlw high (sintable)
		addwfc x1+1,W
		movwf TBLPTRH
		tablrd 0,0,x1+1		; dummy read, update TABLATH
		tlrd 1,x1		; read high byte
		tablrd 0,1,x1+1		; and low byte.
			
		movfp ra+1,WREG		; get LSB of A in B
		movwf rb		; and convert it to a weight factor
		clrf rb+1,F
		bcf ALUSTA,C
		rrcf rb,F
		rrcf rb+1,F
		bcf ALUSTA,C
		rrcf rb,F
		rrcf rb+1,F
		bcf ALUSTA,C
		rrcf rb,F
		rrcf rb+1,F

		m_lda x1		; multiply "next" table value by B
		call m_mult
		m_sta x2		; and save it

		m_ldaconst H'2000'	; calculate 1-weight factor
		m_sub
		m_ldb x0		; and multiply it by "previous" value
		call m_mult

		m_ldb x2		; add the 2 values
		m_add

end_sin		m_ldb sin_saveb		; restore B
		return
		

;----------------------------------------------------------------------------
; m_scalelin :	linear scaling of A, result in WREG (0 to MAXPIXVAL)
;		and in rdiv
;----------------------------------------------------------------------------

m_scalelin	movpf ra,scaletmp	; copy A to scaletmp reg
		movpf ra+1,scaletmp+1
		bcf ALUSTA,C		; divide by 16
		rrcf scaletmp,F		; 2
		rrcf scaletmp+1,F
		bcf ALUSTA,C
		rrcf scaletmp,F		; 4
		rrcf scaletmp+1,F
		bcf ALUSTA,C
		rrcf scaletmp,F		; 8
		rrcf scaletmp+1,F
		bcf ALUSTA,C
		rrcf scaletmp,F		; 16
		rrcf scaletmp+1,F
		tstfsz scaletmp		; if tmp>255, return MAXPIVXVAL
		goto m_scaleover
		movlw MAXPIXVAL		; if tmp>MAXPIXVAL, return MAXPIXVAL
		cpfslt scaletmp+1
		goto m_scaleover
		movfp scaletmp+1,WREG
		goto end_scalelin

m_scaleover	movlw MAXPIXVAL		; return MAXPIXVAL
end_scalelin	movwf rdiv
		return

;----------------------------------------------------------------------------
; m_scalelog : 	logarithmic scaling of A, result in WREG (0 to 127)
;		and in rdiv
;----------------------------------------------------------------------------

		radix dec
logtable	dw -4652, -4599, -4548, -4496, -4445, -4394, -4344, -4294
		dw -4245, -4196, -4147, -4098, -4050, -4002, -3955, -3908
		dw -3861, -3815, -3769, -3723, -3677, -3632, -3587, -3543
		dw -3498, -3454, -3410, -3367, -3324, -3281, -3238, -3196
		dw -3154, -3112, -3071, -3029, -2988, -2947, -2907, -2867
		dw -2826, -2787, -2747, -2708, -2669, -2630, -2591, -2553
		dw -2514, -2476, -2438, -2401, -2363, -2326, -2289, -2253
		dw -2216, -2180, -2143, -2107, -2072, -2036, -2001, -1965
		dw -1930, -1895, -1861, -1826, -1792, -1758, -1724, -1690
		dw -1656, -1623, -1590, -1556, -1523, -1491, -1458, -1425
		dw -1393, -1361, -1329, -1297, -1265, -1234, -1202, -1171
		dw -1140, -1109, -1078, -1047, -1017,  -986,  -956,  -926
		dw  -896,  -866,  -836,  -806,  -777,  -748,  -718,  -689
		dw  -660,  -631,  -603,  -574,  -545,  -517,  -489,  -461
		dw  -433,  -405,  -377,  -349,  -322,  -294,  -267,  -240
		dw  -213,  -186,  -159,  -132,  -105,   -79,   -52,   -26
		radix hex


m_scalelog	tstfsz ra		; if A<32, return 0
		goto log_testover
		movlw D'32'		
		cpfslt ra+1
		goto log_testover
		movlw 0
		goto end_scalelog

log_testover	movlw high (D'032'*MAXPIXVAL)	; if A>32xMAXPIXVAL, 
		cpfsgt ra			; return MAXPIXVAL
		goto log_1
		goto log_scaleover
log_1		cpfseq ra
		goto log_ok
		movlw low (D'032'*MAXPIXVAL)
		cpfslt ra+1
		goto log_scaleover
		
log_ok		clrf logresult,F	; clear result register
		clrf logresult+1,F

		movpf ra,scaletmp	; copy A to scaletmp reg
		movpf ra+1,scaletmp+1	; (A is between 32 and 32xMAXPIXVAL)
		bcf ALUSTA,C		; multiply tmp by 8
		rlcf scaletmp+1,F	; 2
		rlcf scaletmp,F
		bcf ALUSTA,C
		rlcf scaletmp+1,F	; 4
		rlcf scaletmp,F
		bcf ALUSTA,C
		rlcf scaletmp+1,F	; 8
		rlcf scaletmp,F		; (tmp is between 256 and 256xMAXPIXVAL)

		; normalization phase, until tmp < 256
log_normalize	tstfsz scaletmp
		goto log_2
		goto log_endnorm
log_2		movlw low D'4652'	; add 256*ln(2)*MAXPIXVAL/ln(MAXPIXVAL)
		addwf logresult+1,F	; (=4652) to current evaluation
		movlw high D'4652'
		addwfc logresult,F
		bcf ALUSTA,C
		rrcf scaletmp,F		; divide tmp by 2
		rrcf scaletmp+1,F
		goto log_normalize	; and loop

log_endnorm	movlw H'7F'		; tmp is now between 128 and 255
		andwf scaletmp+1,W	; substract 128
		addlw low (logtable)	; and use it as index in logtable
		movwf TBLPTRL
		movlw high (logtable)
		addwfc scaletmp,W
		movwf TBLPTRH
		tablrd 0,0,scaletmp+1	; dummy read, update TABLATH
		tlrd 1,scaletmp		; read high byte
		tablrd 0,1,scaletmp+1	; and low byte.
		movfp scaletmp+1,WREG
		addwf logresult+1,F	; add this value to result
		movfp scaletmp,WREG
		addwf logresult,F

		movfp logresult,WREG	; returned value is high byte
		goto end_scalelog

log_scaleover	movlw MAXPIXVAL
end_scalelog	movwf rdiv
		return

;----------------------------------------------------------------------------
; m_mathtest : Test utility for mathlib functions
;
; to be used for debug only
;----------------------------------------------------------------------------


m_mathtest	m_ldaconst H'23EF'	; (1.123) 
		m_mvab
		m_ldaconst H'B561'	; (-2.332)
		m_lddiv 0
  		nop			; expected : 
; RA = -19103 $B561 -2.331909  RB =   9199 $23EF  1.122925  RDIV =    0 $00

		call m_sin
  		nop			; expected : 
; RA =  -5931 $E8D5 -0.723999  RB =   9199 $23EF  1.122925  RDIV =    0 $00

		call m_mult
  		nop			; expected : 
; RA =  -6660 $E5FC -0.812988  RB =   9199 $23EF  1.122925  RDIV =    0 $00

		m_mvab
		m_ldaconst H'F88B'	; (-0.233)
		m_add
  		nop			; expected : 
; RA =  -8568 $DE88 -1.045898  RB =  -6660 $E5FC -0.812988  RDIV =    0 $00

		movlw D'44'
		movwf h1i
		m_stai h1i
		m_ldaconst 0
		movlw D'44'
		movwf h1i
		m_ldbi h1i
		m_mvba
  		nop			; expected : 
; RA =  -8568 $DE88 -1.045898  RB =  -8568 $DE88 -1.045898  RDIV =    0 $00

		m_ldaconst H'F8DB'	; (-0.2233); 
		m_sub
  		nop			; expected : 
; RA =   6739 $1A53  0.822632  RB =  -8568 $DE88 -1.045898  RDIV =    0 $00

		m_mvab
		m_ldaconst H'470A'	; (2.22)
		m_add
  		nop			; expected : 
; RA =  24925 $615D  3.042603  RB =   6739 $1A53  0.822632  RDIV =    0 $00

		call m_sin
		m_mvab
		m_ldaconst H'F560'	; (-0.332)
		call m_mult
  		nop			; expected : 
; RA =   -268 $FEF4 -0.032715  RB =    809 $0329  0.098755  RDIV =    0 $00

		m_sta h1r
		movlw D'31'
		movwf h2r
		m_lddiv h2r
		call m_divi
  		nop			; expected : 
; RA =     -8 $FFF8 -0.000977  RB =    809 $0329  0.098755  RDIV =   31 $1F

		m_ldb h1r
		m_sub
		call m_mult
  		nop			; expected : 
; RA =     -8 $FFF8 -0.000977  RB =   -268 $FEF4 -0.032715  RDIV =   31 $1F

		m_mvab
		m_lda h1r
		call m_sin
		call m_mult
  		nop			; expected : 
; RA =      0 $0000  0.000000  RB =     -8 $FFF8 -0.000977  RDIV =   31 $1F

		m_ldaconst H'18E2'	; (0.7776)
		call m_scalelin
  		nop			; expected : 
; RA =   6370 $18E2  0.777588  RB =     -8 $FFF8 -0.000977  RDIV =  127 $7F

		m_ldaconst H'C15'	; (0.3776); 
		call m_scalelin
  		nop			; expected : 
; RA =   3093 $0C15  0.377563  RB =     -8 $FFF8 -0.000977  RDIV =   96 $60

  		m_ldaconst H'C15'	; (0.3776)
		m_div2
		call m_scalelin
  		nop			; expected : 
; RA =   1546 $060A  0.188721  RB =     -8 $FFF8 -0.000977  RDIV =   48 $30

		m_ldaconst H'18E2'	; (0.7776); 
		call m_scalelog
  		nop			; expected : 
; RA =   6370 $18E2  0.777588  RB =     -8 $FFF8 -0.000977  RDIV =  127 $7F

		m_ldaconst H'C15'	; (0.3776) 
		call m_scalelog
  		nop			; expected : 
; RA =   3093 $0C15  0.377563  RB =     -8 $FFF8 -0.000977  RDIV =  119 $77

		m_ldaconst H'C15'	; (0.3776) 
		m_div2
		call m_scalelog
  		nop			; expected : 
; RA =   1546 $060A  0.188721  RB =     -8 $FFF8 -0.000977  RDIV =  101 $65

		m_lda h1r
		m_div2
		call m_sin
		m_mvab
		m_ldaconst H'438D'	; (2.111)
		call m_mult
  		nop			; expected : 
; RA =   -280 $FEE8 -0.034180  RB =   -133 $FF7B -0.016235  RDIV =  101 $65
 
		call m_scalelog
  		nop			; expected : 
; RA =   -280 $FEE8 -0.034180  RB =   -133 $FF7B -0.016235  RDIV =    0 $00

		return

;============================================================================
;                             - END OF FILE -
;============================================================================
;============================================================================
; PROJECT     : PIC'SPECTRUM
;
; FILE        : TESTSIG.INC
;
; VERSION     : 1.0
;
; DESCRIPTION :
;
; Test signals generation (for validation of the FFT routines)
;
; A square test signal is generated during ram initialization, and is
; displayed if the Pic'Spectrum is switched on in hold mode.
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================


;----------------------------------------------------------------------------
; test_square : Generate a square signal
;
; On input, amplitude is in math register A, half-period in WREG
;----------------------------------------------------------------------------

test_square	clrf cpti,F		; cpti=index to data
		clrf cptj,F		; cptj=phase
		movwf test_halfp	; test_halfp=halfperiod

testsquare_b	incf cptj,F		; increment phase
		movfp cptj,WREG
		cpfseq test_halfp	; equal to half-period ?
		goto testsquare_norm
		clrf cptj,F		; if yes, reset phase
		m_mvab
		m_ldaconst H'E000'	; and multiply phase by -1
		call m_mult

testsquare_norm	m_stai cpti			; store current amplitude

		incfsz cpti,F
		goto testsquare_b	; and loop

		return


;----------------------------------------------------------------------------
; test_triangle : Generate a triangle signal
;
; On input, step is in math register A, half-period in WREG
;----------------------------------------------------------------------------


test_triangle	clrf cpti,F		; cpti=index to data
		movwf test_halfp	; halfp=halfperiod
		bcf ALUSTA,C
		rrcf WREG,W
		movwf cptj		; cptj=phase (initialised to 50%)
		m_sta test_step		; test_step=step
		m_ldaconst 0
		m_sta test_cval		; test_cval=current value

testtriangle_b	incf cptj,F		; increment phase
		movfp cptj,WREG
		cpfseq test_halfp	; equal to half-period ?
		goto testtriang_norm
		clrf cptj,F		; if yes, reset phase
		m_lda test_step
		m_mvab
		m_ldaconst H'E000'	; and multiply step by -1
		call m_mult
		m_sta test_step

testtriang_norm	m_lda test_cval		; increment value by step value
		m_mvab
		m_lda test_step
		m_add
		m_sta test_cval
		m_stai cpti		; store current amplitude

		incfsz cpti,F
		goto testtriangle_b	; and loop

		return


;============================================================================
;                             - END OF FILE -
;============================================================================
;============================================================================
; PROJECT     : PIC'SPECTRUM
;
; FILE        : FFT.INC
;
; VERSION     : 1.0
;
; DESCRIPTION :
;
; 256 points FFT routines, using s/2/13 format for numeric computations
; (through the fixed.inc library). All data are stored in the internal
; registers of the 17C756 (array DATA).
;
; Execution time on a PIC17C756/32MHz : around 50ms without concurrent
; video generation (resulting in a 90-100ms refresh time with spectrum
; power calculation, analog acquisition and video refresh)
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================



;----------------------------------------------------------------------------
; Complex FFT, radix-1, decimation in place, 128 points
;
; Algorithm from "Numerical recipes in C", manually compiled in assembler
; and adapted...            
;
; Input : 128 complex values (each on 4 bytes), stored in data[0..511]
;         For each data : byte 0 = MSB of real part
;                         byte 1 = LSB of real part
;                         byte 2 = MSB of complex part
;                         byte 3 = LSB of complex part
;
; Replace data[0..511] by its FFT (128 frequencies, complex values)
;----------------------------------------------------------------------------


fft 	nop				; Control point : Input FFT

; ------> initialisation
	clrf j,F			; j=0
					; nn=128 (implicit), n=256 (implicit)

; ------> bit reversal
	clrf i,F			; for(i=0;i<n-1;i+=2) {
iloop1	nop

if1	movfp i,WREG			; if (j>i) {
	cpfsgt j
	goto endif1
    
	m_ldai j			; m_ldai(j)
	m_ldbi i			; m_ldbi(i)
	m_stai i			; m_stai(i)
	m_mvba				; m_mvba()
	m_stai j			; m_stai(j);
	incf j,F
	incf i,F
	m_ldai j			; m_ldai(j+1)
	m_ldbi i			; m_ldbi(i+1)
	m_stai i			; m_stai(i+1)
	m_mvba				; m_mvba()
	m_stai j			; m_stai(j+1)
	decf j,F
	decf i,F

endif1	nop				; } endif

    	movlw D'128'			; m=n>>1
	movwf m

while1	movlw D'2'			; while(m>=2 && j>=m) {
	cpfslt m
	goto $+2
	goto wend1	
	movfp m,WREG
	cpfslt j
	goto $+2
	goto wend1

 	movfp m,WREG			; j-=m
	subwf j,F

	bcf ALUSTA,C			; m>>=1
	rrcf m,F

wloop1	goto while1			; }

wend1	movfp m,WREG			; j+=m
	addwf j,F

inext1	incf i,F			; } next i
	incfsz i,F
	goto iloop1


; ------> FFT itself
  	movlw D'2'			; mmax=2
	movwf mmax

while2	tstfsz mmax			; while(n>mmax) {
	goto $+2
	goto wend2

	movfp mmax, WREG		; istep=mmax<<1
	bcf ALUSTA,C
	rlcf WREG,F
	movwf istep

    	; theta=2pi/mmax
	m_ldaconst H'6488'		; m_ldaconst(3.14159265459) 
	m_lddiv mmax			; m_lddiv(mmax>>1) 
	bcf ALUSTA,C
	rrcf rdiv,F
	call m_divi			; m_divi()
	m_sta theta			; m_sta(&theta)

	; wpr=-2*sin(theta/2)^2
	movlw D'2'			; m_lddiv(2)
	movwf rdiv
	call m_divi			; m_divi()
	call m_sin			; m_sin()
	m_mvab				; m_mvab()
	call m_mult			; m_mult()
	m_mvab				; m_mvab()
	m_ldaconst H'C000'		; m_ldaconst(-2.0)
	call m_mult			; m_mult()
	m_sta wpr			; m_sta(&wpr)

	; wpi=n_sin(theta)
	m_lda theta			; m_lda(theta)
	call m_sin			; m_sin()
	m_sta wpi			; m_sta(&wpi)

	; wr=1, wi=0
	m_ldaconst H'2000'		; m_ldaconst(1.0)
	m_sta wr			; m_sta(&wr)
	m_ldaconst H'0000'		; m_ldaconst(0.0)
	m_sta wi			; m_sta(&wi)

ffttst1	nop

	clrf m,F			; for(m=0;m<mmax-1;m+=2) {
mloop1	movfp mmax,WREG
	decf WREG,W
	cpfslt m
	goto mend1

ffttst2	nop

	movfp m,WREG			; for(i=m;i<n;i+=istep) {
	movwf i
iloop2	nop

	movfp i,WREG			; j=i+mmax
	movwf j
	movfp mmax,WREG
	addwf j,F

ffttst3	nop

	; h1r=wr*data[j]-wi*data[j+1]
	m_lda wi			; m_lda(wi)
	incf j,F			; m_ldbi(j+1)
	m_ldbi j
	decf j,F
	call m_mult			; m_mult()
	m_sta h1r			; m_sta(&h1r)
	m_lda wr			; m_lda(wr)
	m_ldbi j			; m_ldbi(j)
	call m_mult			; m_mult()
	m_ldb h1r			; m_ldb(h1r)
	m_sub				; m_sub()
	m_sta h1r			; m_sta(&h1r)

	; h1i=wr*data[j+1]+wi*data[j]
	m_lda wi			; m_lda(wi)
	m_ldbi j			; m_ldbi(j)
	call m_mult			; m_mult()
	m_sta h1i			; m_sta(&h1i)
	m_lda wr			; m_lda(wr)
	incf j,F			; m_ldbi(j+1)
	m_ldbi j
	decf j,F
	call m_mult			; m_mult()
	m_ldb h1i			; m_ldb(h1i)
	m_add				; m_add()
	m_sta h1i			; m_sta(&h1i)

	; butterfly update, with in-place scaling

	; data[j]=(data[i]-h1r)/2
	m_ldai i			; m_ldai(i)
	m_ldb h1r			; m_ldb(h1r)
	m_sub				; m_sub()
	m_div2				; m_div2()
	m_stai j			; m_stai(j)

	; data[j+1]=(data[i+1]-h1i)/2
	incf i,F			; m_ldai(i+1)
	m_ldai i
	decf i,F
	m_ldb h1i			; m_ldb(h1i)
	m_sub				; m_sub()
	m_div2				; m_div2()
	incf j,F			; m_stai(j+1)
	m_stai j
	decf j,F

	; data[i]=(data[i]+h1r)/2
	m_ldai i			; m_ldai(i)
	m_ldb h1r			; m_ldb(h1r)
	m_add				; m_add()
	m_div2				; m_div2()
	m_stai i			; m_stai(i)

	; data[i+1]=(data[i+1]+h1i)/2 
	incf i,F			; m_ldai(i+1)
	m_ldai i
	decf i,F
	m_ldb h1i			; m_ldb(h1i)
	m_add				; m_add()
	m_div2				; m_div2()
	incf i,F			; m_stai(i+1)
	m_stai i
	decf i,F

inext2	tstfsz istep			; } next i
	goto $+2
	goto iend2
	movfp istep,WREG	
	addwf i,F
	btfss ALUSTA,C
	goto iloop2

	; wtemp=wr
iend2	m_lda wr			; m_lda(wr)
	m_sta wtemp			; m_sta(&wtemp)

	; wr=wr*wpr-wi*wpi+wr
	m_lda wi			; m_lda(wi)
	m_ldb wpi			; m_ldb(wpi)
	call m_mult			; m_mult()
	m_sta h1r			; m_sta(&h1r)
	m_lda wr			; m_lda(wr)
	m_ldb wpr			; m_ldb(wpr)
	call m_mult			; m_mult()
	m_ldb h1r			; m_ldb(h1r)
	m_sub				; m_sub()
	m_ldb wr			; m_ldb(wr)
	m_add				; m_add()
	m_sta wr			; m_sta(&wr)

 	; wi=wi*wpr+wtemp*wpi+wi
	m_lda wtemp			; m_lda(wtemp)
	m_ldb wpi			; m_ldb(wpi)
	call m_mult			; m_mult()
	m_sta h1i			; m_sta(&h1i)
	m_lda wi			; m_lda(wi)
	m_ldb wpr			; m_ldb(wpr)
	call m_mult			; m_mult()
	m_ldb h1i			; m_ldb(h1i)
	m_add				; m_add()
	m_ldb wi			; m_ldb(wi)
	m_add				; m_add()
	m_sta wi			; m_sta(&wi)
    
mnext1	incf m,F			; } next m
	incf m,F
	goto mloop1
mend1	nop

	movfp istep,WREG		; mmax=istep
	movwf mmax

wloop2	goto while2			; } end while
wend2	return


;----------------------------------------------------------------------------
; Real FFT
;
; Algorithm from "Numerical recipes in C", manually compiled in assembler
; and adapted...            
;
; Calculate FFT of a set of 256 real values stored in data[0..511] 
; (2 bytes per value, MSB first).
;
; Replace these data by the positive frequency half of the FFT  
; (128 frequencies, complex values). First and last frequencies (which are 
; real) are in data[1] and data[2] respectively.
; 
; Method : consider the 256 real values as interleaved real/imaginary parts
; of 128 complex values. Do a complex 128 points FFT, and find back the 
; FFT of the real numbers from the output of the complex FFT...
;
; Nota : this method allow to do a real FFT with 30-40% less calculations
; and, more important, 50% less RAM requirement.
;----------------------------------------------------------------------------

realfft	nop				; control point, N=256 (implicit)

; ------> do a complex FFT of half the number of points, odd real points
;         as real data, even real points as imaginary data 

  	call fft

;-------> and find the good values from the result... 

    	; theta=2pi/n
	m_ldaconst H'6488'		; m_ldaconst(3.14159265459) 
	movlw D'128'			; m_lddiv(n>>1) 
	movwf rdiv
	call m_divi			; m_divi()
	m_sta theta			; m_sta(&theta)

	; wpr=-2*sin(theta/2)^2
	movlw D'2'			; m_lddiv(2)
	movwf rdiv
	call m_divi			; m_divi()
	call m_sin			; m_sin()
	m_mvab				; m_mvab()
	call m_mult			; m_mult()
	m_mvab				; m_mvab()
	m_ldaconst H'C000'		; m_ldaconst(-2.0)
	call m_mult			; m_mult()
	m_sta wpr			; m_sta(&wpr)

	; wpi=n_sin(theta)
	m_lda theta			; m_lda(theta)
	call m_sin			; m_sin()
	m_sta wpi			; m_sta(&wpi)

	; wr=1+wpr, wi=wpi
	m_ldb wpr			; m_ldb(wpr)
	m_ldaconst H'2000'		; m_ldaconst(1.0)
	m_add				; m_add()
	m_sta wr			; m_sta(&wr)
	m_lda wpi			; m_lda(wpi)
	m_sta wi			; m_sta(&wi)

	movlw D'2'			; for(i=2;i<=(n>>2);i++) {
	movwf i
iloop3	movlw D'64'
	cpfsgt i
	goto $+2
	goto iend3

	movfp i,WREG			; i1=i+i-2
	movwf i1
	addwf i1,F
	movlw D'2'
	subwf i1,F

	movfp i1,WREG			; i2=1+i1
	movwf i2
	incf i2,F

	movfp i2,WREG			; i3=n-i2+1
	comf WREG,W
	incf WREG,W
	incf WREG,W
	movwf i3

	incf WREG,W
	movwf i4			; i4=1+i3

	; h1r=(data[i1]+data[i3])/2
	m_ldai i1			; m_ldai(i1)
	m_ldbi i3			; m_ldbi(i3)
	m_add				; m_add()
	m_div2				; m_div2()
	m_sta h1r			; m_sta(&h1r)

	; h1i=(data[i2]-data[i4])/2
	m_ldai i2			; m_ldai(i2)
	m_ldbi i4			; m_ldbi(i4)
	m_sub				; m_sub()
	m_div2				; m_div2()
	m_sta h1i			; m_sta(&h1i)

	; h2r=(data[i2]+data[i4])/2
	m_ldai i2			; m_ldai(i2)
	m_ldbi i4			; m_ldbi(i4)
	m_add				; m_add()
	m_div2				; m_div2()
	m_sta h2r			; m_sta(&h2r)

	; h2i=-(data[i1]-data[i3])/2
	m_ldai i3			; m_ldai(i3)
	m_ldbi i1			; m_ldbi(i1)
	m_sub				; m_sub()
	m_div2				; m_div2()
	m_sta h2i			; m_sta(&h2i)

	; data[i1]=h1r+wr*h2r-wi*h2i
	m_lda wi			; m_lda(wi)
	m_ldb h2i			; m_ldb(h2i)
	call m_mult			; m_mult()
	m_sta wtemp			; m_sta(&wtemp)
	m_lda wr			; m_lda(wr)
	m_ldb h2r			; m_ldb(h2r)
	call m_mult			; m_mult()
	m_ldb wtemp			; m_ldb(wtemp)
	m_sub				; m_sub()
	m_ldb h1r			; m_ldb(h1r)
	m_add				; m_add()
	m_stai i1			; m_stai(i1)

	; data[i2]=h1i+wr*h2i+wi*h2r
	m_lda wi			; m_lda(wi)
	m_ldb h2r			; m_ldb(h2r)
	call m_mult			; m_mult()
	m_sta wtemp			; m_sta(&wtemp)
	m_lda wr			; m_lda(wr)
	m_ldb h2i			; m_ldb(h2i)
	call m_mult			; m_mult()
	m_ldb wtemp			; m_ldb(wtemp)
	m_add				; m_add()
	m_ldb h1i			; m_ldb(h1i)
	m_add				; m_add()
	m_stai i2			; m_stai(i2)

	; data[i3]=h1r-wr*h2r+wi*h2i
	m_lda wr			; m_lda(wr)
	m_ldb h2r			; m_ldb(h2r)
	call m_mult			; m_mult()
	m_sta wtemp			; m_sta(&wtemp)
	m_lda wi			; m_lda(wi)
	m_ldb h2i			; m_ldb(h2i)
	call m_mult			; m_mult()
	m_ldb wtemp			; m_ldb(wtemp)
	m_sub				; m_sub()
	m_ldb h1r			; m_ldb(h1r)
	m_add				; m_add()
	m_stai i3			; m_stai(i3)

	; data[i4]=-h1i+wr*h2i+wi*h2r
	m_lda wr			; m_lda(wr)
	m_ldb h2i			; m_ldb(h2i)
	call m_mult			; m_mult()
	m_sta wtemp			; m_sta(&wtemp)
	m_lda wi			; m_lda(wi)
	m_ldb h2r			; m_ldb(h2r)
	call m_mult			; m_mult()
	m_ldb wtemp			; m_ldb(wtemp)
	m_add				; m_add()
	m_ldb h1i			; m_ldb(h1i)
	m_sub				; m_sub()
	m_stai i4			; m_stai(i4)

	; wtemp=wr 
	m_lda wr			; m_lda(wr)
	m_sta wtemp			; m_sta(&wtemp)

	; wr=wr*wpr-wi*wpi+wr
	m_lda wi			; m_lda(wi)
	m_ldb wpi			; m_ldb(wpi)
	call m_mult			; m_mult()
	m_sta h1r			; m_sta(&h1r)
	m_lda wr			; m_lda(wr)
	m_ldb wpr			; m_ldb(wpr)
	call m_mult			; m_mult()
	m_ldb h1r			; m_ldb(h1r)
	m_sub				; m_sub()
	m_ldb wr			; m_ldb(wr)
	m_add				; m_add()
	m_sta wr			; m_sta(&wr)

	; wi=wi*wpr+wtemp*wpi+wi
	m_lda wi			; m_lda(wi)
	m_ldb wpr			; m_ldb(wpr)
	call m_mult			; m_mult()
	m_sta h1r			; m_sta(&h1r)
	m_lda wtemp			; m_lda(wtemp)
	m_ldb wpi			; m_ldb(wpi)
	call m_mult			; m_mult()
	m_ldb h1r			; m_ldb(h1r)
	m_add				; m_add()
	m_ldb wi			; m_ldb(wi)
	m_add				; m_add()
	m_sta wi			; m_sta(&wi)


inext3	incf i,F				; } next i
	goto iloop3
iend3	nop

; ------> special case of the 2 first data

	; h1r=data[0]
	movlw 0				; m_ldai(0)
	movwf i
	m_ldai i
	m_sta h1r			; m_sta(&h1r)

	; data[0]=h1r+data[1]
	movlw 1				; m_ldbi(1)
	movwf i
	m_ldbi i
	m_add				; m_add()
	movlw 0				; m_stai(0)
	movwf i
	m_stai i

	; data[1]=h1r-data[1]
	m_lda h1r			; m_lda(h1r)
	movlw 1				; m_ldbi(1)
	movwf i
	m_ldbi i
	m_sub				; m_sub()
	movlw 1				; m_stai(1)
	movwf i
	m_stai i

endrft	return



;============================================================================
;                             - END OF FILE -
;============================================================================
;============================================================================
; PROJECT     : PIC'SPECTRUM
;
; FILE        : POWERS.INC
;
; VERSION     : 1.0
;
; DESCRIPTION :
;
; Power spectrum calculation starting with the result of the real FFT.
; Result power is scaled (lin or log) and stored in the display buffer
; area (dispbuf) : 1 byte per frequency (1 to 126)
;
; This file define also the routine used by the interrupt routine to
; access the display buffer (with is paged)
;
; The display buffer table ("dispbuf") is a 2x64 bytes array, each of the
; two blocks being at at fixed adress ($20 to $5F) in the banks 2 and 3.
;
; Nota : dispbuf(0) (DC frequency) is not displayed.
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================


;----------------------------------------------------------------------------
; dispbufwr :	Write a value in the given display buffer cell
;		On input : 	WREG = index (0 to 127)
;				RDIV = value (0 to MAXPIXVAL)
;		On output : bank selected = zone_main
;----------------------------------------------------------------------------

dispbufwr	macro
		movlr 2			; start with bank 2
		btfsc WREG,6		; select the good bank
		bsf BSR,4		; based on 6th bit of index
		andlw B'00111111'	; clear 2 MSB bits
		addlw H'20'		; add $20 (data start at $20)
		movwf FSR0		; and use it as an index
		movfp rdiv,INDF0	; to store value
		BANKSEL zone_main	; reset bank register
		endm


;----------------------------------------------------------------------------
; dispbufrd :	Read a value from the given display buffer cell
;		On input : 	WREG = index (0 to 127)
;		On output : 	WREG = value (0 to MAXPIXVAL)
;				bank selected = zone_irq
;
; WARNING : 	Time critical routine ! In particular, execution time should
;		be always exactly the same (if not, pixels won't be aligned
;		anymore...)
;
; DURATION : 8 cycles (1.00 microsecond at 32MHz)
;----------------------------------------------------------------------------

dispbufrd	macro
		movlr 2			; start with bank 2
		btfsc WREG,6		; select the good bank
		bsf BSR,4		; based on 6th bit of index
		andlw B'00111111'	; clear 2 MSB bits
		addlw H'20'		; add $20 (data start at $20)
		movwf FSR0		; and use it as an index
		movfp INDF0,WREG	; to read value
		BANKSEL zone_irq	; reset bank register
		endm


;----------------------------------------------------------------------------
; intpowerlin :	Calculate power spectrum for the complex value stored
;		in RA and RB, scale it with a linear scale (result from 0
;		to MAXPIXVAL) and store the result in RDIV
;----------------------------------------------------------------------------

		; A=(A/2)^2+(B/2)^2 (divide by 2 to exclude overflow)

intpowerlin	m_sta h1r		; m_sta(&h1r)
		m_mvba			; m_mvba()
		m_div2			; m_div2() 
		m_mvab			; m_mvab() 
		call m_mult		; m_mult() 
		m_sta h2r		; m_sta(&h2r)
		m_lda h1r		; m_lda(h1r)
		m_div2			; m_div2()
		m_mvab			; m_mvab() 
		call m_mult		; m_mult()
		m_ldb h2r		; m_ldb(h2r)
		m_add			; m_add()
		call m_scalelin		; m_scalelin()
		return


;----------------------------------------------------------------------------
; intpowerlog :	Calculate power spectrum for the complex value stored
;		in RA and RB, scale it with a log scale (result from 0
;		to MAXPIXVAL) and store the result in RDIV
;----------------------------------------------------------------------------

		; A=(A/2)^2+(B/2)^2 (divide by 2 to exclude overflow)

intpowerlog	m_sta h1r		; m_sta(&h1r)
		m_mvba			; m_mvba()
		m_div2			; m_div2() 
		m_mvab			; m_mvab() 
		call m_mult		; m_mult() 
		m_sta h2r		; m_sta(&h2r)
		m_lda h1r		; m_lda(h1r)
		m_div2			; m_div2()
		m_mvab			; m_mvab() 
		call m_mult		; m_mult()
		m_ldb h2r		; m_ldb(h2r)
		m_add			; m_add()
		call m_scalelog		; m_scalelog()
		return


;----------------------------------------------------------------------------
; powerlin :	Calculate power spectrum for the complex spectrum stored
;		in "data", scale it with a linear scale (result from 0
;		to MAXPIXVAL) and store the result in "dispbuf"
;
;		Nota : last frequency (number 128) is discarted
;----------------------------------------------------------------------------

powerlin	nop

;--------------> Special case of the first value (real)
		clrf rdiv,F
		m_ldai rdiv		; m_ldai(0)
		m_ldbi rdiv		; m_ldbi(0)
		call intpowerlin	; intpower()
		movlw 0
		dispbufwr		; dispbuf[0]=(unsigned char)rdiv

;--------------> General case
		clrf i,F		; for (i=1;i<SLENGTH/2;i++) {
		incf i,F
iloop4		nop
		
		movfp i,WREG		; i2=(i<<1)
		movwf i2
		bcf ALUSTA,C
		rlcf i2,F

		m_ldai i2		; m_ldai(i2)
		incf i2,F		; m_ldbi(i2+1)
		m_ldbi i2

		call intpowerlin	; intpower(); 
		movfp i,WREG		; dispbuf[i]=(unsigned char)rdiv
		dispbufwr

inext4		incf i,F		; } next i
		movlw D'128'
		cpfseq i
		goto iloop4

		return


;----------------------------------------------------------------------------
; powerlog :	Calculate power spectrum for the complex spectrum stored
;		in "data", scale it with a log scale (result from 0
;		to MAXPIXVAL) and store the result in "dispbuf"
;----------------------------------------------------------------------------

powerlog	nop

;--------------> Special case of the first value (real)
		clrf rdiv,F
		m_ldai rdiv		; m_ldai(0)
		m_ldbi rdiv		; m_ldbi(0)
		call intpowerlog	; intpower()
		movlw 0
		dispbufwr		; dispbuf[0]=(unsigned char)rdiv

;--------------> General case
		clrf i,F		; for (i=1;i<SLENGTH/2;i++) {
		incf i,F
iloop5		nop
		
		movfp i,WREG		; i2=(i<<1)
		movwf i2
		bcf ALUSTA,C
		rlcf i2,F

		m_ldai i2		; m_ldai(i2)
		incf i2,F		; m_ldbi(i2+1)
		m_ldbi i2

		call intpowerlog	; intpower(); 
		movfp i,WREG		; dispbuf[i]=(unsigned char)rdiv
		dispbufwr

inext5		incf i,F		; } next i
		movlw D'128'
		cpfseq i
		goto iloop5

		return


;============================================================================
;                             - END OF FILE -
;============================================================================
;============================================================================
; PROJECT     : UPS'SPECTRUM
;
; FILE        : IRQ.INC
;
; VERSION     : 1.0
;
; DESCRIPTION : 
;
; Handler of the timer0 interrupt, in charge of all real time tasks,
; mainly analog signal acquisition and software video generation...
;
; WARNING : These routines are VERY time critical, in particular for the
; video generation. Do not change the duration of any routine (even by adding
; or deleting only one instruction) without a deep analysis. Effects can go
; from misaligned pixels to... loss of video synchronisation.
; The main time dependencies are indicated in the source (see "PT" checkpoints
; and "RT" comments) but I'm not sure that the list is complete !
;
; Comment : Some of the routines may seems a little "bulk force" and 
; excessively rom expensive, but think twice about the performances required 
; before replacing everything by loop ! In fact, we only do manually what
; modern compilers do as part as their optimization phase... loop unrolling !
;
;============================================================================
;                Developped & Copyrighted by Robert LACOSTE
;============================================================================


;----------------------------------------------------------------------------
; Management of analog acquisitions and generation of Hsync signal
;
; Check if an analog acquisition is requested by the main program.
; If so do the acquisition of 256 samples (one each 2 video scan lines, 
; giving a sample rate of 31.5KHz/2=15.75KHz)
; 
; Synchronisation with the main program is done through acq_request flag
; and num_sample register :
;
; Main program :
; - To launch a sampling, put acq_request=1 and reset num_sample
; - wait for acq_request to be back 0
; 
; This interrupt routine :
; - if acq_request=0 => Nothing to do
; - if acq_request=1 => Launch acquisition and put acq_request=2
; - if acq_request=2 => Get result and store it in (num_sample)
;                       Increment num_sample
;                       If <256, put acq_request=1 (sampling period)
;                       else put acq_request=0
;
; The HSync signal is generated within this routine, insuring that its length
; is constant (=30 clock cycles) and its position fixed.
; 
; Warning : The duration of this routine must be CONSTANT, whatever tests
; results are ! (now, its 37 cycles)
;
; Warning : on input, bankselect should be on zone_irq
;----------------------------------------------------------------------------

manage_adc	macro

		bsf PORTC,4		; set RC4 (HSync signal active)

;--> RT constraint !!! From PT1, delay >= 0.94µS=8 instr (pre-HSync blanking)
;                      and fixed (whatever test & branch are executed)

;--> RT checkpoint PT2 (start of HSync signal)

;--> RT checkpoint PT0A	(start of ADC management)

		movlw 2			; acq_request = 2 ?
		cpfseq acq_request
		goto adc_not2

;--> Acq_request=2

		; save RA (because we must use a non banked memory)

		movpf ra, tmpi
		movpf ra+1, tmpi+1

		; scale ADC value (0 to 653536 -> -8192 to +8192)

		movlb 5
		movpf ADRESL,ra+1	; get ADC value
		movpf ADRESH,ra		; and scale it to our floating format
		bcf ALUSTA,C
		rrcf ra,F		; divide by 4
		rrcf ra+1,F
		bcf ALUSTA,C
		rrcf ra,F
		rrcf ra+1,F
		movlw H'20'		; substract H'2000'
		subwf ra,F		; it's now from -1.0 to +1.0
		
		; store ADC value in data(num_sample)

		movlb 5			; select register bank 5
		movfp num_sample, WREG	
		movlr 0			; start with bank 0
		btfsc WREG,7		; select the good bank
		bsf BSR,5
		btfsc WREG,6		; based on 2 first bits of WREG
		bsf BSR,4
		bcf ALUSTA,C		; multiply by 2
		rlcf WREG,1
		bsf WREG,7		; and set high bit (data start at $80)
		movwf FSR0		; and use it as an index
		movfp ra,INDF0		; to store msb value...

		movlb 1
		bcf PORTC,4		; clear RC4 (HSync signal inactive)

;--> RT constraint !!! From PT2, delay = 3.77µS=30 instr (HSync duration)
;                      and fixed (whatever test & branch are executed)
;--> RT checkpoint PT3 (end of HSync signal)

		incf FSR0,1
		movfp ra+1,INDF0	; ... and lsb value
		BANKSEL zone_irq	; reset bank register
	
		; increment num_sample and update aca_request

		clrf acq_request,F	; acq_request=0
		movlw 1
		incfsz num_sample,F	; increment num_sample
		movwf acq_request	; if <>0, acq_request=1

		; restore RA
		movfp tmpi, ra
		movfp tmpi+1, ra+1

		goto end_manage_adc
		
adc_not2	nop			; acq_request <> 2
		nop
		nop
		nop
		nop
		nop
		nop			; delay nop's in order to be in
		nop			; synch with the switch case above
		nop
		nop
		nop
		nop
		movlw 1
		cpfseq acq_request	; acq_request=1 ?
		goto adc_0
		goto adc_1

;--> Acq_request=0

adc_0		nop			; acq=request is 0. Nothing to do
		nop			; except wait...
		nop
		nop
		nop
		nop
		nop
		nop
		movlb 1
		bcf PORTC,4		; clear RC4 (HSync signal inactive)

;--> RT constraint !!! From PT2, delay = 3.77µS=30 instr (HSync duration)
;                      and fixed (whatever test & branch are executed)

;--> RT checkpoint PT3 (end of HSync signal)

		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		goto end_manage_adc

;--> Acq_request=1

adc_1		nop

		movlb 5			; start ADC conversion
		bsf ADCON0,GO
		movlw 2			; acq_request=2
		movwf acq_request
		nop
		nop
		movlb 1
		bcf PORTC,4		; clear RC4 (HSync signal inactive)

;--> RT constraint !!! From PT2, delay = 3.77µS=30 instr (HSync duration)
;                      and fixed (whatever test & branch are executed)

;--> RT checkpoint PT3 (end of HSync signal)

		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop			; and wait

end_manage_adc	nop
		endm

;--> RT constraint !!! From PT0A, delay FIXED (now 42 instructions cycles)


;----------------------------------------------------------------------------
; Routine called on timer0 interrupt
;
; This routine is called at 31.5KHz (horizontal refresh rate for 640x350)
; and do the main real time tasks :
;
; - Registers saving
; - Analog acquisition
; - Video generation
; - Registers restoring
;
; Warning : Time from interrupt to video generation must be rigourously
; stable.
;----------------------------------------------------------------------------

it_timer	movpf BSR,sv_bsr	; save BSR 

;--> RT checkpoint PT0 (start of interrupt routine)

		BANKSEL zone_irq
		movpf ALUSTA,sv_alusta	; save ALUSTA
		movwf sv_wreg		; save WREG
		movpf FSR0,sv_fsr0	; save FSR0

		movlb 0
		clrf PORTB,F		; switch video off 

;--> RT checkpoint PT1 (start of horizontal blanking zone)

		movlb 1
		bsf PORTD,2		; set RD2 (debug line : IRQ going on)

		movlw high INITTIM	; reload timer
		movwf tmpi
		movlw low INITTIM
		movwf TMR0L
		movfp tmpi,TMR0H

		manage_adc		; ADC management, 35 clock cycles

		movlw 1			; increment scan_line
		addwf scan_line+1,F	; (rollback to 0 done in the last's
		clrf WREG,W		; line sub-routine)
		addwfc scan_line,F

		movlb 0			; select registers bank 0 for video

		; Based on scan_line value (from 1 to 449), calculate
		; the address of the line management routine

		movlw low jump_table	; calculate jump address
		addwf scan_line+1,W
		movwf tmpi
		movlw high jump_table
		addwfc scan_line,W
		movwf PCLATH
		
;--> RT constraint !!! From PT3 to first pixel display, 
;                      delay > 1.89µS=15 instr (post HSync blanking)

		movfp tmpi, PCL		; and jump to it !

		; at the end of the scan line display, the called routine
		; will jump back to resume_irq

resume_irq	movlb 1
		bcf PORTD,2		; clear RD2 (debug line : IRQ going on)

		BANKSEL zone_irq
		movfp sv_alusta,ALUSTA	; restore ALUSTA
		movfp sv_fsr0,FSR0	; and FSR0
		movfp sv_wreg,WREG	; and WREG
		movfp sv_bsr,BSR	; and BSR

		retfie			; return from interrupt

;--> RT constraint !!! From PT0, delay < 30µS=240 instr (Timer0 irq period)
;                      it lets 240-71=169 instructions for the scan_x routines

;----------------------------------------------------------------------------
; Jump address table
;
; For each scan line (1 to 449), calculated jump to the good management
; routine, depending on the scan line number
;----------------------------------------------------------------------------
		
jump_table	goto scan_blanking	; scan 000, should not occur
		goto scan_vsynch_on	; scan 001, switch on VSynch
		goto scan_blanking	; scan 002, vertical blanking
		goto scan_vsynch_off	; scan 003, switch off VSynch
		goto scan_blanking	; scan 004, vertical blanking
		goto scan_blanking	; scan 005, vertical blanking
		goto scan_blanking	; scan 006, vertical blanking
		goto scan_blanking	; scan 007, vertical blanking
		goto scan_blanking	; scan 008, vertical blanking
		goto scan_blanking	; scan 009, vertical blanking
		goto scan_blanking	; scan 010, vertical blanking
		goto scan_blanking	; scan 011, vertical blanking
		goto scan_blanking	; scan 012, vertical blanking
		goto scan_blanking	; scan 013, vertical blanking
		goto scan_blanking	; scan 014, vertical blanking
		goto scan_blanking	; scan 015, vertical blanking
		goto scan_blanking	; scan 016, vertical blanking
		goto scan_blanking	; scan 017, vertical blanking
		goto scan_blanking	; scan 018, vertical blanking
		goto scan_blanking	; scan 019, vertical blanking
		goto scan_blanking	; scan 020, vertical blanking
		goto scan_blanking	; scan 021, vertical blanking
		goto scan_blanking	; scan 022, vertical blanking
		goto scan_blanking	; scan 023, vertical blanking
		goto scan_blanking	; scan 024, vertical blanking
		goto scan_blanking	; scan 025, vertical blanking
		goto scan_blanking	; scan 026, vertical blanking
		goto scan_blanking	; scan 027, vertical blanking
		goto scan_blanking	; scan 028, vertical blanking
		goto scan_blanking	; scan 029, vertical blanking
		goto scan_blanking	; scan 030, vertical blanking
		goto scan_blanking	; scan 031, vertical blanking
		goto scan_blanking	; scan 032, vertical blanking
		goto scan_blanking	; scan 033, vertical blanking
		goto scan_blanking	; scan 034, vertical blanking
		goto scan_blanking	; scan 035, vertical blanking
		goto scan_blanking	; scan 036, vertical blanking
		goto scan_blanking	; scan 037, vertical blanking
		goto scan_blanking	; scan 038, vertical blanking
		goto scan_blanking	; scan 039, vertical blanking
		goto scan_blanking	; scan 040, vertical blanking
		goto scan_blanking	; scan 041, vertical blanking
		goto scan_blanking	; scan 042, vertical blanking
		goto scan_blanking	; scan 043, vertical blanking
		goto scan_blanking	; scan 044, vertical blanking
		goto scan_blanking	; scan 045, vertical blanking
		goto scan_blanking	; scan 046, vertical blanking
		goto scan_blanking	; scan 047, vertical blanking
		goto scan_blanking	; scan 048, vertical blanking
		goto scan_blanking	; scan 049, vertical blanking
		goto scan_blanking	; scan 050, vertical blanking
		goto scan_blanking	; scan 051, vertical blanking
		goto scan_blanking	; scan 052, vertical blanking
		goto scan_blanking	; scan 053, vertical blanking
		goto scan_blanking	; scan 054, vertical blanking
		goto scan_blanking	; scan 055, vertical blanking
		goto scan_blanking	; scan 056, vertical blanking
		goto scan_blanking	; scan 057, vertical blanking
		goto scan_blanking	; scan 058, vertical blanking
		goto scan_blanking	; scan 059, vertical blanking
		goto scan_blanking	; scan 060, vertical blanking
		goto scan_blanking	; scan 061, vertical blanking
		goto scan_empty		; scan 062 (sl 000), empty line
		goto scan_empty		; scan 063 (sl 001), empty line
		goto scan_empty		; scan 064 (sl 002), empty line
		goto scan_empty		; scan 065 (sl 003), empty line
		goto scan_empty		; scan 066 (sl 004), empty line
		goto scan_empty		; scan 067 (sl 005), empty line
		goto scan_empty		; scan 068 (sl 006), empty line
		goto scan_empty		; scan 069 (sl 007), empty line
		goto scan_empty		; scan 070 (sl 008), empty line
		goto scan_empty		; scan 071 (sl 009), empty line
		goto scan_empty		; scan 072 (sl 010), empty line
		goto scan_empty		; scan 073 (sl 011), empty line
		goto scan_empty		; scan 074 (sl 012), empty line
		goto scan_empty		; scan 075 (sl 013), empty line
		goto scan_empty		; scan 076 (sl 014), empty line
		goto scan_empty		; scan 077 (sl 015), empty line
		goto scan_empty		; scan 078 (sl 016), empty line
		goto scan_empty		; scan 079 (sl 017), empty line
		goto scan_empty		; scan 080 (sl 018), empty line
		goto scan_empty		; scan 081 (sl 019), empty line
		goto scan_empty		; scan 082 (sl 020), empty line
		goto scan_empty		; scan 083 (sl 021), empty line
		goto scan_empty		; scan 084 (sl 022), empty line
		goto scan_hscalelong	; scan 085 (sl 023), h.scale long sep
		goto scan_hscalelong	; scan 086 (sl 024), h.scale long sep
		goto scan_hscalelong	; scan 087 (sl 025), h.scale long sep
		goto scan_hscalelong	; scan 088 (sl 026), h.scale long sep
		goto scan_hscalelong	; scan 089 (sl 027), h.scale long sep
		goto scan_hscalelong	; scan 090 (sl 028), h.scale long sep
		goto scan_hscalelong	; scan 091 (sl 029), h.scale long sep
		goto scan_hscalelong	; scan 092 (sl 030), h.scale long sep
		goto scan_hscaleshort	; scan 093 (sl 031), h.scale short sep
		goto scan_hscaleshort	; scan 094 (sl 032), h.scale short sep
		goto scan_hscaleshort	; scan 095 (sl 033), h.scale short sep
		goto scan_hscaleshort	; scan 096 (sl 034), h.scale short sep
		goto scan_hscaleshort	; scan 097 (sl 035), h.scale short sep
		goto scan_hscaleshort	; scan 098 (sl 036), h.scale short sep
		goto scan_hscaleshort	; scan 099 (sl 037), h.scale short sep
		goto scan_empty		; scan 100 (sl 038), empty line
		goto scan_empty		; scan 101 (sl 039), empty line
		goto scan_empty		; scan 102 (sl 040), empty line
		goto scan_hscaleline	; scan 103 (sl 041), h. plain line
		goto scan_sepline	; scan 104 (sl 042), frequencies sep.
		goto scan_freqline	; scan 105 (sl 043), freq 001
		goto scan_sepline	; scan 106 (sl 044), frequencies sep.
		goto scan_freqline	; scan 107 (sl 045), freq 002
		goto scan_sepline	; scan 108 (sl 046), frequencies sep.
		goto scan_freqline	; scan 109 (sl 047), freq 003
		goto scan_sepline	; scan 110 (sl 048), frequencies sep.
		goto scan_freqline	; scan 111 (sl 049), freq 004
		goto scan_sepline	; scan 112 (sl 050), frequencies sep.
		goto scan_freqline	; scan 113 (sl 051), freq 005
		goto scan_sepline	; scan 114 (sl 052), frequencies sep.
		goto scan_freqline	; scan 115 (sl 053), freq 006
		goto scan_sepline	; scan 116 (sl 054), frequencies sep.
		goto scan_freqline	; scan 117 (sl 055), freq 007
		goto scan_sepline	; scan 118 (sl 056), frequencies sep.
		goto scan_freqline	; scan 119 (sl 057), freq 008
		goto scan_sepline	; scan 120 (sl 058), frequencies sep.
		goto scan_freqline	; scan 121 (sl 059), freq 009
		goto scan_sepline	; scan 122 (sl 060), frequencies sep.
		goto scan_freqline	; scan 123 (sl 061), freq 010
		goto scan_sepline	; scan 124 (sl 062), frequencies sep.
		goto scan_freqline	; scan 125 (sl 063), freq 011
		goto scan_sepline	; scan 126 (sl 064), frequencies sep.
		goto scan_freqline	; scan 127 (sl 065), freq 012
		goto scan_sepline	; scan 128 (sl 066), frequencies sep.
		goto scan_freqline	; scan 129 (sl 067), freq 013
		goto scan_sepline	; scan 130 (sl 068), frequencies sep.
		goto scan_freqline	; scan 131 (sl 069), freq 014
		goto scan_sepline	; scan 132 (sl 070), frequencies sep.
		goto scan_freqline	; scan 133 (sl 071), freq 015
		goto scan_sepline	; scan 134 (sl 072), frequencies sep.
		goto scan_freqline	; scan 135 (sl 073), freq 016
		goto scan_vscaleshort	; scan 136 (sl 074), v.scale short s.
		goto scan_freqline	; scan 137 (sl 075), freq 017
		goto scan_sepline	; scan 138 (sl 076), frequencies sep.
		goto scan_freqline	; scan 139 (sl 077), freq 018
		goto scan_sepline	; scan 140 (sl 078), frequencies sep.
		goto scan_freqline	; scan 141 (sl 079), freq 019
		goto scan_sepline	; scan 142 (sl 080), frequencies sep.
		goto scan_freqline	; scan 143 (sl 081), freq 020
		goto scan_sepline	; scan 144 (sl 082), frequencies sep.
		goto scan_freqline	; scan 145 (sl 083), freq 021
		goto scan_sepline	; scan 146 (sl 084), frequencies sep.
		goto scan_freqline	; scan 147 (sl 085), freq 022
		goto scan_sepline	; scan 148 (sl 086), frequencies sep.
		goto scan_freqline	; scan 149 (sl 087), freq 023
		goto scan_sepline	; scan 150 (sl 088), frequencies sep.
		goto scan_freqline	; scan 151 (sl 089), freq 024
		goto scan_sepline	; scan 152 (sl 090), frequencies sep.
		goto scan_freqline	; scan 153 (sl 091), freq 025
		goto scan_sepline	; scan 154 (sl 092), frequencies sep.
		goto scan_freqline	; scan 155 (sl 093), freq 026
		goto scan_sepline	; scan 156 (sl 094), frequencies sep.
		goto scan_freqline	; scan 157 (sl 095), freq 027
		goto scan_sepline	; scan 158 (sl 096), frequencies sep.
		goto scan_freqline	; scan 159 (sl 097), freq 028
		goto scan_sepline	; scan 160 (sl 098), frequencies sep.
		goto scan_freqline	; scan 161 (sl 099), freq 029
		goto scan_sepline	; scan 162 (sl 100), frequencies sep.
		goto scan_freqline	; scan 163 (sl 101), freq 030
		goto scan_sepline	; scan 164 (sl 102), frequencies sep.
		goto scan_freqline	; scan 165 (sl 103), freq 031
		goto scan_sepline	; scan 166 (sl 104), frequencies sep.
		goto scan_freqline	; scan 167 (sl 105), freq 032
		goto scan_vscaleshort	; scan 168 (sl 106), v.scale short s.
		goto scan_freqline	; scan 169 (sl 107), freq 033
		goto scan_sepline	; scan 170 (sl 108), frequencies sep.
		goto scan_freqline	; scan 171 (sl 109), freq 034
		goto scan_sepline	; scan 172 (sl 110), frequencies sep.
		goto scan_freqline	; scan 173 (sl 111), freq 035
		goto scan_sepline	; scan 174 (sl 112), frequencies sep.
		goto scan_freqline	; scan 175 (sl 113), freq 036
		goto scan_sepline	; scan 176 (sl 114), frequencies sep.
		goto scan_freqline	; scan 177 (sl 115), freq 037
		goto scan_sepline	; scan 178 (sl 116), frequencies sep.
		goto scan_freqline	; scan 179 (sl 117), freq 038
		goto scan_sepline	; scan 180 (sl 118), frequencies sep.
		goto scan_freqline	; scan 181 (sl 119), freq 039
		goto scan_sepline	; scan 182 (sl 120), frequencies sep.
		goto scan_freqline	; scan 183 (sl 121), freq 040
		goto scan_sepline	; scan 184 (sl 122), frequencies sep.
		goto scan_freqline	; scan 185 (sl 123), freq 041
		goto scan_sepline	; scan 186 (sl 124), frequencies sep.
		goto scan_freqline	; scan 187 (sl 125), freq 042
		goto scan_sepline	; scan 188 (sl 126), frequencies sep.
		goto scan_freqline	; scan 189 (sl 127), freq 043
		goto scan_sepline	; scan 190 (sl 128), frequencies sep.
		goto scan_freqline	; scan 191 (sl 129), freq 044
		goto scan_sepline	; scan 192 (sl 130), frequencies sep.
		goto scan_freqline	; scan 193 (sl 131), freq 045
		goto scan_sepline	; scan 194 (sl 132), frequencies sep.
		goto scan_freqline	; scan 195 (sl 133), freq 046
		goto scan_sepline	; scan 196 (sl 134), frequencies sep.
		goto scan_freqline	; scan 197 (sl 135), freq 047
		goto scan_sepline	; scan 198 (sl 136), frequencies sep.
		goto scan_freqline	; scan 199 (sl 137), freq 048
		goto scan_vscaleshort	; scan 200 (sl 138), v.scale short s.
		goto scan_freqline	; scan 201 (sl 139), freq 049
		goto scan_sepline	; scan 202 (sl 140), frequencies sep.
		goto scan_freqline	; scan 203 (sl 141), freq 050
		goto scan_sepline	; scan 204 (sl 142), frequencies sep.
		goto scan_freqline	; scan 205 (sl 143), freq 051
		goto scan_sepline	; scan 206 (sl 144), frequencies sep.
		goto scan_freqline	; scan 207 (sl 145), freq 052
		goto scan_sepline	; scan 208 (sl 146), frequencies sep.
		goto scan_freqline	; scan 209 (sl 147), freq 053
		goto scan_sepline	; scan 210 (sl 148), frequencies sep.
		goto scan_freqline	; scan 211 (sl 149), freq 054
		goto scan_sepline	; scan 212 (sl 150), frequencies sep.
		goto scan_freqline	; scan 213 (sl 151), freq 055
		goto scan_sepline	; scan 214 (sl 152), frequencies sep.
		goto scan_freqline	; scan 215 (sl 153), freq 056
		goto scan_sepline	; scan 216 (sl 154), frequencies sep.
		goto scan_freqline	; scan 217 (sl 155), freq 057
		goto scan_sepline	; scan 218 (sl 156), frequencies sep.
		goto scan_freqline	; scan 219 (sl 157), freq 058
		goto scan_sepline	; scan 220 (sl 158), frequencies sep.
		goto scan_freqline	; scan 221 (sl 159), freq 059
		goto scan_sepline	; scan 222 (sl 160), frequencies sep.
		goto scan_freqline	; scan 223 (sl 161), freq 060
		goto scan_sepline	; scan 224 (sl 162), frequencies sep.
		goto scan_freqline	; scan 225 (sl 163), freq 061
		goto scan_sepline	; scan 226 (sl 164), frequencies sep.
		goto scan_freqline	; scan 227 (sl 165), freq 062
		goto scan_sepline	; scan 228 (sl 166), frequencies sep.
		goto scan_freqline	; scan 229 (sl 167), freq 063
		goto scan_sepline	; scan 230 (sl 168), frequencies sep.
		goto scan_freqline	; scan 231 (sl 169), freq 064
		goto scan_vscaleshort	; scan 232 (sl 170), v.scale short s.
		goto scan_freqline	; scan 233 (sl 171), freq 065
		goto scan_sepline	; scan 234 (sl 172), frequencies sep.
		goto scan_freqline	; scan 235 (sl 173), freq 066
		goto scan_sepline	; scan 236 (sl 174), frequencies sep.
		goto scan_freqline	; scan 237 (sl 175), freq 067
		goto scan_sepline	; scan 238 (sl 176), frequencies sep.
		goto scan_freqline	; scan 239 (sl 177), freq 068
		goto scan_sepline	; scan 240 (sl 178), frequencies sep.
		goto scan_freqline	; scan 241 (sl 179), freq 069
		goto scan_sepline	; scan 242 (sl 180), frequencies sep.
		goto scan_freqline	; scan 243 (sl 181), freq 070
		goto scan_sepline	; scan 244 (sl 182), frequencies sep.
		goto scan_freqline	; scan 245 (sl 183), freq 071
		goto scan_sepline	; scan 246 (sl 184), frequencies sep.
		goto scan_freqline	; scan 247 (sl 185), freq 072
		goto scan_sepline	; scan 248 (sl 186), frequencies sep.
		goto scan_freqline	; scan 249 (sl 187), freq 073
		goto scan_sepline	; scan 250 (sl 188), frequencies sep.
		goto scan_freqline	; scan 251 (sl 189), freq 074
		goto scan_sepline	; scan 252 (sl 190), frequencies sep.
		goto scan_freqline	; scan 253 (sl 191), freq 075
		goto scan_sepline	; scan 254 (sl 192), frequencies sep.
		goto scan_freqline	; scan 255 (sl 193), freq 076
		goto scan_sepline	; scan 256 (sl 194), frequencies sep.
		goto scan_freqline	; scan 257 (sl 195), freq 077
		goto scan_sepline	; scan 258 (sl 196), frequencies sep.
		goto scan_freqline	; scan 259 (sl 197), freq 078
		goto scan_sepline	; scan 260 (sl 198), frequencies sep.
		goto scan_freqline	; scan 261 (sl 199), freq 079
		goto scan_sepline	; scan 262 (sl 200), frequencies sep.
		goto scan_freqline	; scan 263 (sl 201), freq 080
		goto scan_vscalelong	; scan 264 (sl 202), v.scale long s.
		goto scan_freqline	; scan 265 (sl 203), freq 081
		goto scan_sepline	; scan 266 (sl 204), frequencies sep.
		goto scan_freqline	; scan 267 (sl 205), freq 082
		goto scan_sepline	; scan 268 (sl 206), frequencies sep.
		goto scan_freqline	; scan 269 (sl 207), freq 083
		goto scan_sepline	; scan 270 (sl 208), frequencies sep.
		goto scan_freqline	; scan 271 (sl 209), freq 084
		goto scan_sepline	; scan 272 (sl 210), frequencies sep.
		goto scan_freqline	; scan 273 (sl 211), freq 085
		goto scan_sepline	; scan 274 (sl 212), frequencies sep.
		goto scan_freqline	; scan 275 (sl 213), freq 086
		goto scan_sepline	; scan 276 (sl 214), frequencies sep.
		goto scan_freqline	; scan 277 (sl 215), freq 087
		goto scan_sepline	; scan 278 (sl 216), frequencies sep.
		goto scan_freqline	; scan 279 (sl 217), freq 088
		goto scan_sepline	; scan 280 (sl 218), frequencies sep.
		goto scan_freqline	; scan 281 (sl 219), freq 089
		goto scan_sepline	; scan 282 (sl 220), frequencies sep.
		goto scan_freqline	; scan 283 (sl 221), freq 090
		goto scan_sepline	; scan 284 (sl 222), frequencies sep.
		goto scan_freqline	; scan 285 (sl 223), freq 091
		goto scan_sepline	; scan 286 (sl 224), frequencies sep.
		goto scan_freqline	; scan 287 (sl 225), freq 092
		goto scan_sepline	; scan 288 (sl 226), frequencies sep.
		goto scan_freqline	; scan 289 (sl 227), freq 093
		goto scan_sepline	; scan 290 (sl 228), frequencies sep.
		goto scan_freqline	; scan 291 (sl 229), freq 094
		goto scan_sepline	; scan 292 (sl 230), frequencies sep.
		goto scan_freqline	; scan 293 (sl 231), freq 095
		goto scan_sepline	; scan 294 (sl 232), frequencies sep.
		goto scan_freqline	; scan 295 (sl 233), freq 096
		goto scan_vscaleshort	; scan 296 (sl 234), v.scale short s.
		goto scan_freqline	; scan 297 (sl 235), freq 097
		goto scan_sepline	; scan 298 (sl 236), frequencies sep.
		goto scan_freqline	; scan 299 (sl 237), freq 098
		goto scan_sepline	; scan 300 (sl 238), frequencies sep.
		goto scan_freqline	; scan 301 (sl 239), freq 099
		goto scan_sepline	; scan 302 (sl 240), frequencies sep.
		goto scan_freqline	; scan 303 (sl 241), freq 100
		goto scan_sepline	; scan 304 (sl 242), frequencies sep.
		goto scan_freqline	; scan 305 (sl 243), freq 101
		goto scan_sepline	; scan 306 (sl 244), frequencies sep.
		goto scan_freqline	; scan 307 (sl 245), freq 102
		goto scan_sepline	; scan 308 (sl 246), frequencies sep.
		goto scan_freqline	; scan 309 (sl 247), freq 103
		goto scan_sepline	; scan 310 (sl 248), frequencies sep.
		goto scan_freqline	; scan 311 (sl 249), freq 104
		goto scan_sepline	; scan 312 (sl 250), frequencies sep.
		goto scan_freqline	; scan 313 (sl 251), freq 105
		goto scan_sepline	; scan 314 (sl 252), frequencies sep.
		goto scan_freqline	; scan 315 (sl 253), freq 106
		goto scan_sepline	; scan 316 (sl 254), frequencies sep.
		goto scan_freqline	; scan 317 (sl 255), freq 107
		goto scan_sepline	; scan 318 (sl 256), frequencies sep.
		goto scan_freqline	; scan 319 (sl 257), freq 108
		goto scan_sepline	; scan 320 (sl 258), frequencies sep.
		goto scan_freqline	; scan 321 (sl 259), freq 109
		goto scan_sepline	; scan 322 (sl 260), frequencies sep.
		goto scan_freqline	; scan 323 (sl 261), freq 110
		goto scan_sepline	; scan 324 (sl 262), frequencies sep.
		goto scan_freqline	; scan 325 (sl 263), freq 111
		goto scan_sepline	; scan 326 (sl 264), frequencies sep.
		goto scan_freqline	; scan 327 (sl 265), freq 112
		goto scan_vscaleshort	; scan 328 (sl 266), v.scale short s.
		goto scan_freqline	; scan 329 (sl 267), freq 113
		goto scan_sepline	; scan 330 (sl 268), frequencies sep.
		goto scan_freqline	; scan 331 (sl 269), freq 114
		goto scan_sepline	; scan 332 (sl 270), frequencies sep.
		goto scan_freqline	; scan 333 (sl 271), freq 115
		goto scan_sepline	; scan 334 (sl 272), frequencies sep.
		goto scan_freqline	; scan 335 (sl 273), freq 116
		goto scan_sepline	; scan 336 (sl 274), frequencies sep.
		goto scan_freqline	; scan 337 (sl 275), freq 117
		goto scan_sepline	; scan 338 (sl 276), frequencies sep.
		goto scan_freqline	; scan 339 (sl 277), freq 118
		goto scan_sepline	; scan 340 (sl 278), frequencies sep.
		goto scan_freqline	; scan 341 (sl 279), freq 119
		goto scan_sepline	; scan 342 (sl 280), frequencies sep.
		goto scan_freqline	; scan 343 (sl 281), freq 120
		goto scan_sepline	; scan 344 (sl 282), frequencies sep.
		goto scan_freqline	; scan 345 (sl 283), freq 121
		goto scan_sepline	; scan 346 (sl 284), frequencies sep.
		goto scan_freqline	; scan 347 (sl 285), freq 122
		goto scan_sepline	; scan 348 (sl 286), frequencies sep.
		goto scan_freqline	; scan 349 (sl 287), freq 123
		goto scan_sepline	; scan 350 (sl 288), frequencies sep.
		goto scan_freqline	; scan 351 (sl 289), freq 124
		goto scan_sepline	; scan 352 (sl 290), frequencies sep.
		goto scan_freqline	; scan 353 (sl 291), freq 125
		goto scan_sepline	; scan 354 (sl 292), frequencies sep.
		goto scan_freqline	; scan 355 (sl 293), freq 126
		goto scan_sepline	; scan 356 (sl 294), frequencies sep.
		goto scan_freqline	; scan 357 (sl 295), freq 127
		goto scan_sepline	; scan 358 (sl 296), frequencies sep.
		goto scan_empty		; scan 359 (sl 297), empty line
		goto scan_empty		; scan 360 (sl 298), empty line
		goto scan_empty		; scan 361 (sl 299), empty line
		goto scan_empty		; scan 362 (sl 300), empty line
		goto scan_empty		; scan 363 (sl 301), empty line
		goto scan_empty		; scan 364 (sl 302), empty line
		goto scan_empty		; scan 365 (sl 303), empty line
		goto scan_empty		; scan 366 (sl 304), empty line
		goto scan_empty		; scan 367 (sl 305), empty line
		goto scan_empty		; scan 368 (sl 306), empty line
		goto scan_empty		; scan 369 (sl 307), empty line
		goto scan_empty		; scan 370 (sl 308), empty line
		goto scan_empty		; scan 371 (sl 309), empty line
		goto scan_empty		; scan 372 (sl 310), empty line
		goto scan_empty		; scan 373 (sl 311), empty line
		goto scan_empty		; scan 374 (sl 312), empty line
		goto scan_empty		; scan 375 (sl 313), empty line
		goto scan_empty		; scan 376 (sl 314), empty line
		goto scan_empty		; scan 377 (sl 315), empty line
		goto scan_empty		; scan 378 (sl 316), empty line
		goto scan_empty		; scan 379 (sl 317), empty line
		goto scan_empty		; scan 380 (sl 318), empty line
		goto scan_empty		; scan 381 (sl 319), empty line
		goto scan_empty		; scan 382 (sl 320), empty line
		goto scan_empty		; scan 383 (sl 321), empty line
		goto scan_empty		; scan 384 (sl 322), empty line
		goto scan_empty		; scan 385 (sl 323), empty line
		goto scan_empty		; scan 386 (sl 324), empty line
		goto scan_titlempty	; scan 387 (sl 325), empty title
		goto scan_titlempty	; scan 388 (sl 326), empty title
		goto scan_titlempty	; scan 389 (sl 327), empty title
		goto scan_titlempty	; scan 390 (sl 328), empty title
		goto scan_titlempty	; scan 391 (sl 329), empty title
		goto scan_titlempty	; scan 392 (sl 330), empty title
		goto scan_title0	; scan 393 (sl 331), title line 0
		goto scan_title0	; scan 394 (sl 332), title line 0
		goto scan_title1	; scan 395 (sl 333), title line 1
		goto scan_title1	; scan 396 (sl 334), title line 1
		goto scan_title2	; scan 397 (sl 335), title line 2
		goto scan_title2	; scan 398 (sl 336), title line 2
		goto scan_title3	; scan 399 (sl 337), title line 3
		goto scan_title3 	; scan 400 (sl 338), title line 3
		goto scan_title4	; scan 401 (sl 339), title line 4
		goto scan_title4	; scan 402 (sl 340), title line 4
		goto scan_title5	; scan 403 (sl 341), title line 5
		goto scan_title5	; scan 404 (sl 342), title line 5
		goto scan_title6	; scan 405 (sl 343), title line 6
		goto scan_title6	; scan 406 (sl 344), title line 6
		goto scan_titlempty	; scan 407 (sl 345), empty title
		goto scan_titlempty	; scan 408 (sl 346), empty title
		goto scan_titlempty	; scan 409 (sl 347), empty title
		goto scan_titlempty	; scan 410 (sl 348), empty title
		goto scan_titlempty	; scan 411 (sl 349), empty title
		goto scan_blanking	; scan 412, vertical blanking
		goto scan_blanking	; scan 413, vertical blanking
		goto scan_blanking	; scan 414, vertical blanking
		goto scan_blanking	; scan 415, vertical blanking
		goto scan_blanking	; scan 416, vertical blanking
		goto scan_blanking	; scan 417, vertical blanking
		goto scan_blanking	; scan 418, vertical blanking
		goto scan_blanking	; scan 419, vertical blanking
		goto scan_blanking	; scan 420, vertical blanking
		goto scan_blanking	; scan 421, vertical blanking
		goto scan_blanking	; scan 422, vertical blanking
		goto scan_blanking	; scan 423, vertical blanking
		goto scan_blanking	; scan 424, vertical blanking
		goto scan_blanking	; scan 425, vertical blanking
		goto scan_blanking	; scan 426, vertical blanking
		goto scan_blanking	; scan 427, vertical blanking
		goto scan_blanking	; scan 428, vertical blanking
		goto scan_blanking	; scan 429, vertical blanking
		goto scan_blanking	; scan 430, vertical blanking
		goto scan_blanking	; scan 431, vertical blanking
		goto scan_blanking	; scan 432, vertical blanking
		goto scan_blanking	; scan 433, vertical blanking
		goto scan_blanking	; scan 434, vertical blanking
		goto scan_blanking	; scan 435, vertical blanking
		goto scan_blanking	; scan 436, vertical blanking
		goto scan_blanking	; scan 437, vertical blanking
		goto scan_blanking	; scan 438, vertical blanking
		goto scan_blanking	; scan 439, vertical blanking
		goto scan_blanking	; scan 440, vertical blanking
		goto scan_blanking	; scan 441, vertical blanking
		goto scan_blanking	; scan 442, vertical blanking
		goto scan_blanking	; scan 443, vertical blanking
		goto scan_blanking	; scan 444, vertical blanking
		goto scan_blanking	; scan 445, vertical blanking
		goto scan_blanking	; scan 446, vertical blanking
		goto scan_blanking	; scan 447, vertical blanking
		goto scan_blanking	; scan 448, vertical blanking
		goto scan_rstscanl	; scan 449, reset scan_line


;----------------------------------------------------------------------------
; Soft generation of a vertical blanking line
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_blanking	goto resume_irq		; Nothing to do as video already off !


;----------------------------------------------------------------------------
; Soft generation of a vertical blanking line with switch on of Vsynch
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_vsynch_on	movlb 1
		bcf PORTC,6		; RC6=0 (Vsynch active)
		incf frame_num,F	; increment frame number
		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of a vertical blanking line with switch off of Vsynch
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_vsynch_off	movlb 1
		bsf PORTC,6		; RC6=1 (Vsynch inactive)
		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of a blank screen line (background color)
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_empty	movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color
		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of a frequency line
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_freqline	movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		movlw D'103'		; calculate frequency number
		subwf scan_line+1,W	; (=(scan_line-103)/2)
		movwf tmpi
		bcf ALUSTA,C
		rrcf tmpi,W

		dispbufrd		; read display buffer value (8 cycles)		
		andlw B'01111111'	; be sure it is <128
		movwf tmpi		; and store it in tmpi

		sublw low endfreqline	; calculate jump address
		movwf tmpi2+1		; (endfreqline-freq value)
		movlw high endfreqline	; store msb in PCLATH and lsb in tmpi2+1
		movwf tmpi2
		clrf WREG,W
		subwfb tmpi2,F
		movfp tmpi2,PCLATH

		movlw BKG_COLOR
		movwf tmpcolor
		movlw SLINE_COLOR
		movwf PORTB		; draw vertical line
		movfp tmpcolor,PORTB	; and return to background color

		clrf WREG,W
		cpfsgt tmpi		; if value 0
		goto resume_irq		; return

		movlw FREQ_COLOR	; else
		movwf PORTB		; draw frequency line

		movfp tmpi2+1,PCL	; and jump to precalculated address

		nop
		nop
start_wait128	nop
		nop			; 128 nop's
		nop			; in order to have a cycle per cycle
		nop			; delay, a jump is done to the 
		nop			; precalculated nop in this list !
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop		
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop	
		nop
		nop	
endfreqline	movlw BKG_COLOR
		movwf PORTB		; and return to background color

		goto resume_irq

;----------------------------------------------------------------------------
; Soft generation of a separating line between 2 frequency lines
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_sepline	movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		nop
		nop
		nop			; serie of nop's in order to
		nop			; be sure that the vertical
		nop			; line will be aligned with 
					; the one for frequency lines !
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop

		nop
		nop
		nop
		nop
		nop
		nop
		nop

		movlw BKG_COLOR
		movwf tmpcolor
		movlw SLINE_COLOR
		movwf PORTB		; draw vertical line
		movfp tmpcolor,PORTB	; and return to background color

		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of a separating line with a "short" scale indicator
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_vscaleshort movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		nop
		nop
		nop			; serie of nop's in order to
		nop			; be sure that the vertical
		nop			; line will be aligned with 
					; the one for frequency lines !
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop

		nop
		nop
		nop
		nop
		nop
		movlw SHORTS_COLOR
		movwf PORTB		; draw the small indicator
		nop

		movlw BKG_COLOR
		movwf tmpcolor
		movwf PORTB		; return to background color
		movlw SLINE_COLOR
		movwf PORTB		; draw vertical line
		movfp tmpcolor,PORTB	; and return to background color

		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of a separating line with a "long" scale indicator
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_vscalelong	movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		nop
		nop
		nop			; serie of nop's in order to
		nop			; be sure that the vertical
		nop			; line will be aligned with 
					; the one for frequency lines !
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		movlw LONGS_COLOR
		movwf PORTB		; draw the long indicator

		nop
		nop
		nop

		movlw BKG_COLOR
		movwf tmpcolor
		movwf PORTB		; return to background color
		movlw SLINE_COLOR
		movwf PORTB		; draw vertical line
		movfp tmpcolor,PORTB	; and return to background color

		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of the horizontal scale "long" steps
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_hscalelong	movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		movwf tmpi2		; save color for background
		movlw LONGS_COLOR
		movwf tmpi		; save color for long steps drawing		
		movlw BKG_COLOR
		movwf tmpi+1		; save color for short steps drawing

		movlb 0
		btfsc PORTB,7		; log mode ?
		goto scale_lin_m	; if not, draw lin scale
		goto scale_log_m	; else draw log scale
		
scale_lin_m	nop			; time correction for btfsc
scale_lin_m2	nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		movfp tmpi,PORTB	;col 0 -> long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 10
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;-> short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col20
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col30
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 40
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 50
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi,PORTB	;col 60->long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 70
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 80
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 90
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 100
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 110
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi,PORTB	;col 120->long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 127

		goto resume_irq


scale_log_m	nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop

		movfp tmpi,PORTB	;col 0->long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 10
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col20
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col30
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi,PORTB	;col 40->long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 50
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 60
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 70
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi,PORTB	;col 80->long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 90
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 100
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 110
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi+1,PORTB	;->short
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi,PORTB	;col 120->long
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB
		movfp tmpi2,PORTB	;col 127

		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of the horizontal scale "short" steps
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_hscaleshort movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		movwf tmpi2		; save color for background
		movlw LONGS_COLOR
		movwf tmpi		; save color for long steps drawing		
		movlw SHORTS_COLOR
		movwf tmpi+1		; save color for short steps drawing

		movlb 0
		btfsc PORTB,7		; log mode ?
		goto scale_lin_m	; if not, draw lin scale
		goto scale_log_m	; else draw log scale


;----------------------------------------------------------------------------
; Soft generation of the horizontal scale plain line
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_hscaleline	movlb 0
		movlw BKG_COLOR
		movwf PORTB		; set background color

		nop
		nop
		nop			; serie of nop's in order to
		nop			; be sure that the vertical
		nop			; line will be aligned with 
					; the one for frequency lines !
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop

		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop
		nop

		movlw SLINE_COLOR
		movwf PORTB		; draw vertical line

		goto start_wait128	; and wait for end of active line


;----------------------------------------------------------------------------
; Soft generation of a blank screen line (background title color)
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_titlempty	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB		; set background color
		goto resume_irq


;----------------------------------------------------------------------------
; Soft generation of the title lines
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

; Title content :
; *               ****   *****   ***    *  ***   *****   *****   ***   *****  ****   *   *  *   *               *
; ***             *   *    *    *   *  *  *   *  *    *  *      *   *    *    *   *  *   *  ** **             ***
; *****           *   *    *    *         *      *    *  *      *        *    *   *  *   *  * * *           *****
; *******         ****     *    *          ***   *****   ***    *        *    ****   *   *  *   *         *******
; *********       *        *    *             *  *       *      *        *    * *    *   *  *   *       *********
; ***********     *        *    *   *     *   *  *       *      *   *    *    *  *   *   *  *   *     ***********
; *************   *      *****   ***       ***   *       *****   ***     *    *   *   ***   *   *   *************
;
; Hold sign content :
;  
;  * *   * * 
; *  *   *  *
; *  *****  * 
; *  *   *  *
;  * *   * *
;  
; The following routines display each line of the previous strings, scan line
; per scan line. No other way to do cycle per cycle video generation (of course
; it's possible to implement a character set map, but not useful in this case)
;
; Of course the following routines where generated automaticaly ! (seems like a
; compiler job, no ?)


; Generation of title0

scan_title0	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color
		goto resume_irq			;and return

; Generation of title1

scan_title1	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color

		movlb 0
		btfsc PORTB,6			;mode hold ?
		goto resume_irq			;if not, return
		btfsc frame_num,5		;blinking test
		goto resume_irq			;if off return

		movlw HOLD_COLOR		;store hold color
		movwf tmpi+1			;in tmpi+1
		movfp tmpi,PORTB		;and display "hold" sign	
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		goto resume_irq			;and return

; Generation of title2

scan_title2	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color

		movlb 0
		btfsc PORTB,6			;mode hold ?
		goto resume_irq			;if not, return
		btfsc frame_num,5		;blinking test
		goto resume_irq			;if off return

		movlw HOLD_COLOR		;store hold color
		movwf tmpi+1			;in tmpi+1
		movfp tmpi,PORTB		;and display "hold" sign	
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB

		goto resume_irq			;and return

; Generation of title3

scan_title3	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color

		movlb 0
		btfsc PORTB,6			;mode hold ?
		goto resume_irq			;if not, return
		btfsc frame_num,5		;blinking test
		goto resume_irq			;if off return

		movlw HOLD_COLOR		;store hold color
		movwf tmpi+1			;in tmpi+1
		movfp tmpi,PORTB		;and display "hold" sign	
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB

		goto resume_irq			;and return

; Generation of title4

scan_title4	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color

		movlb 0
		btfsc PORTB,6			;mode hold ?
		goto resume_irq			;if not, return
		btfsc frame_num,5		;blinking test
		goto resume_irq			;if off return

		movlw HOLD_COLOR		;store hold color
		movwf tmpi+1			;in tmpi+1
		movfp tmpi,PORTB		;and display "hold" sign	
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB

		goto resume_irq			;and return

; Generation of title5

scan_title5	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color

		movlb 0
		btfsc PORTB,6			;mode hold ?
		goto resume_irq			;if not, return
		btfsc frame_num,5		;blinking test
		goto resume_irq			;if off return

		movlw HOLD_COLOR		;store hold color
		movwf tmpi+1			;in tmpi+1
		movfp tmpi,PORTB		;and display "hold" sign	
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		goto resume_irq			;and return

; Generation of title6

scan_title6	movlb 0
		movlw BKGTITLE_COLOR
		movwf PORTB			;set background color
		movlw TITLE_COLOR		;store title color
		movwf tmpi+1			;in tmpi+1
		movlw BKGTITLE_COLOR		;and background color
		movwf tmpi			;in tmpi

		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB

		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi,PORTB
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on
		movfp tmpi+1,PORTB		;Pixel on

		movfp tmpi,PORTB		;reset to background color
		goto resume_irq			;and return


;----------------------------------------------------------------------------
; Soft generation of a vertical blanking line with scan_line reset
; 
; Warning : all scan_X routines should execute in less than 169 instructions
;----------------------------------------------------------------------------

scan_rstscanl	clrf scan_line,F	; reset scanline (will be incremented
		clrf scan_line+1,F	; to 1 at next interrupt)
		goto resume_irq	


;============================================================================
;                             - END OF FILE -
;============================================================================

Oliver Antony Broad of Coaxial Power Systems Ltd Says:

Regarding the comments about AN542 it sounds to me as if the apnote simply lacked a 'window', and was doing exactly what a 'by the book' FFT should do. In an exercise once I was required to simulate a wien bridge and investigate the output purity, the software was also very sensitive to whether an integer number of cycles were processed. I was suprised at this as it was the evaluation version of a professional CAD package.

See:

Questions: