;
; ***************************************************************************
; ***  Bubble Software Parallax to PIC Source Converter. Copyright 1999.  ***
; ***  http://www.picnpoke.com                 email: sales@picnpoke.com  ***
; ***************************************************************************
;
; by FredMaher Madrid 10 Nov 02, Rewritten for SX by James Newton Feb 03.
; Using an extension of the >4 add 3 algorithm

;	device  sx18
	P = pic16c54
	#include <16c54.inc>   ; processor assembler definitions
	_CONFIG _xt_osc & _wdt_off & _protect_off
 reset   start:

BCDdigits equ d'5'
BINdigits equ d'3'

       org 16
bcd  Res BCDdigits
bin  Res BINdigits

;IFNDEF count
count           Res d'1'
;	ENDIF
;IFNDEF temp
temp            Res d'1'
;	ENDIF

;
 org  0
Start:
;-----------------------------------------------------------------
;Hex(Binary) to BCD routine
;-----------------------------------------------------------------
Main:
             MOVLW BCDdigits            
             MOVWF temp
             MOVLW bcd                  
             MOVWF fsr                  
BCDclear:
             CLRF indf                  
             INCF fsr                   
             DECFSZ temp                
             GOTO BCDclear_
	
Testvals:
             MOVLW 0x00FF               
             MOVWF bin                  
             MOVLW 0x00FF               
             MOVWF bin+1                
             MOVLW 0x0F                 
             MOVWF bin+2                

             CALL bin2bcd_              
	
Convend:  ; remove when in main prg
             GOTO Convend_              ; remove when in main prg

;-----------------------------------------------------------
; End main Bin Bcd
;------------------------------------------------------------

bin2bcd:
             MOVLW BINdigits*8          ; count max value
             MOVWF count
	
Shifting:
             MOVF count                 
             BTFSC status,z             
             RETLW 0h                   ; bin number is now converted 2 bcd
             DECF count                 
	
;----------------------------
; Now left shift all registers

             BCF status,c               
             MOVLW BINdigits            
             MOVWF temp
             MOVLW bin                  
             MOVWF fsr
BINrlLoop:
             RLF indf                   
             INCF fsr                   
             DECFSZ temp                
             GOTO BINrlLoop_

             MOVLW BCDdigits            
             MOVWF temp
             MOVLW bcd                  
             MOVWF fsr
BCDrlLoop:
             RLF indf                   
             INCF fsr                   
             DECFSZ temp                
             GOTO BCDrlLoop_


; next step check those which are >4 and add 3

             MOVF count                 
             BTFSC status,z             ; finish without testing >4
             RETLW 0h                   

Nibtests: ;Test BCD, high and low nibbles. If greater than 4 ( or 40) add 3 (or 30)
             MOVLW BCDdigits            
             MOVWF temp
             MOVLW bcd                  
             MOVWF fsr
BCDadjLoop:
             MOVLW 0x0B                 ;(16-5)
             ADDWF indf,w               ;DC set if carry from bit 3 to 4
             MOVLW 0x03                 ; >4 add3
             BTFSC status,dc            
             ADDWF indf                 

             MOVLW 0x00B0               ; is high nibble more than 5?
             ADDWF indf,w               
             MOVLW 0x30                 ; add 3 to high nibble
             BTFSC status,c             
             ADDWF indf                 
             INCF fsr                   
             DECFSZ temp                
             GOTO BCDadjLoop_
	
             GOTO Shifting_             
             
             
             end