Hi Andy.

Squeezing the lemon :)

incf	reg,F	;INCF    REG
movlw	0x66	;MOVLW   0x06
addwf	reg,F	;ADDWF   REG
skpndc		;SKPDC
andlw	0xF0	;SUBWF   REG
skpnc		;MOVLW   0x60
andlw	0x0F	;ADDWF   REG
subwf	reg,F	;SKPC
		;SUBWF   REG	;;btw here Cy is always=1


movlw	0x01	;MOVLW   1
subwf	reg,W	;SUBWF   REG
skpdc		;MOVLW   0x06
xorlw	0x06	;SKPDC
skpc		;XORWF   REG
xorlw	0x60	;MOVLW   0x60
movwf	reg	;SKPC
		;XORWF   REG


I think it is in piclist archive somewhere.


WBR Dmitry.



Andrew Warren wrote:
> 
> Luis:
> 
> This comes up every once in a while and is likely to be in the
> archives somewhere.
> 
> The last time I answered the question, I came up with these.  I
> didn't assemble or test them, but no one complained that they failed
> to work...
> 
> To increment one byte:
> 
>     INCF    REG
> 
>     MOVLW   0x06
>     ADDWF   REG
>     SKPDC
>     SUBWF   REG
> 
>     MOVLW   0x60
>     ADDWF   REG
>     SKPC
>     SUBWF   REG
> 
> To decrement one byte:
> 
>     MOVLW   1
>     SUBWF   REG
> 
>     MOVLW   0x06
>     SKPDC
>     XORWF   REG
> 
>     MOVLW   0x60
>     SKPC
>     XORWF   REG
> 
> The Carry flag is valid after each of those, so first inc/dec the low
> byte, then use the carry to decide whether to inc/dec the high byte.
> 
> -Andy
> 
> === Andrew Warren - fastfwd@ix.netcom.com
> 
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist