Hi Dwayne,

As I am also interested in generating optimized assembler for multiplying=20
by painfull constants I decided to take the plunge and embed the code in a=
=20
web page (you wont need to compile anything now just plug in your numbers)

It is at http://xcprod.com/pic_mult_html.html

There are some optimization you will be able to perform which will depend=20
on the range of numbers you will be using.

Also plugging in 171 shows an interesting repeating pattern which could be=
=20
converted into a couple of subroutines
e.g.

; res =3D x * 171
; res =3D x * 0xAB
; res =3D x * 2^8 - x * 2^6 - x * 2^4 - x * 2^2 - x
; where arg0:arg1 =3D x

start:

;=3D=3D=3D=3D=3D=3D change this

;; res :=3D arg
;	movf	arg0,w
;	movwf	res0
;	movf	arg1,w
;	movwf	res1
;; res :=3D res << 8
;	movf	res0,w
;	movwf	res1
;	clrf	res0

;=3D=3D=3D=3D=3D=3D to this

; res :=3D arg << 8
 	movf	arg0,w
 	movwf	res1
 	clrf	res0
;=3D=3D=3D=3D=3D=3D

;=3D=3D=3D=3D=3D=3D remove this code if we use arg instead of tmp
;	to do all the shifting and subtracting but
;	beware the comments will need to be adjusted
; tmp :=3D arg
 	movf	arg0,w
 	movwf	tmp0
 	movf	arg1,w
 	movwf	tmp1
;=3D=3D=3D=3D=3D=3D

; tmp :=3D arg << 0; res :=3D res - tmp
 	call	just_sub

; tmp :=3D arg << 2; res :=3D res - tmp
 	call	shift_and_sub

; tmp :=3D arg << 4; res :=3D res - tmp
 	call	shift_and_sub

; tmp :=3D arg << 6; res :=3D res - tmp
 	call	shift_and_sub

 	return

shift_and_sub:
; tmp :=3D tmp << 2
 	bcf	STATUS,C
 	rlf	tmp0
 	rlf	tmp1
 	bcf	STATUS,C
 	rlf	tmp0
 	rlf	tmp1

 	; NOTE: drop through is intensional

just_sub:
; res :=3D res - tmp
 	bsf	STATUS,C
 	movf	tmp0,w
 	subwf	res0
 	btfss	STATUS,C
 	decf	res1
 	movf	tmp1,w
 	subwf	res1

 	return

Regards
Sergio
--=20
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