hi,
this macro is 8 instructions long as yours, so
no improvements in it; another way to do same

variable sbl=0

; decrement three-byte value (low byte at low address)
decf3 macro var
    decf var,F
    incf var,W
    btfss STATUS,Z
    goto _sbl#v(sbl)
    decf var+1,F
    incf var+1,W
    btfsc STATUS,Z
    decf var+2,F
_sbl#v(sbl):
sbl = sbl+1
endm


i tried to extend it to 4-byte decrement and here is it:

; decrement four-byte value
decf4 macro var
 decf var,F
 incf var,W
 btfss STATUS,Z
 goto _sbl#v(sbl)
 decf var+1,F
 incf var+1,W
 btfss STATUS,Z
 goto _sbl#v(sbl)
 decf var+2,F
 incf var+2,W
 btfsc STATUS,Z
 decf var+3,F
_sbl#v(sbl):
sbl = sbl+1
 endm

so, four instructions per byte should be added.

Ivan Cenov
okto7@botev.ttm.bg
http://www.geocities.com/SiliconValley/Network/9276/
Do what have to do, let happens what it wants.

-----Original Message-----
From: Bob Blick <bob@ted.net>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: 12 ˉ‹—–˜ 1998 ‹., –ÝØŠˆ 19:35
Subject: 3 byte decrement


>Hi Everyone,
>
>Usually I don't pay any attention to optimizing code, if it works I use
>it, but this morning I'm feeling picky. No where in my notes do I have a
>decrement for more than a 2 byte number. I want 3 bytes. This is what I
>came up with. It looks stupid to me. Feel free to come up with something
>better.  It's for midrange pics and does not use any temporary registers.
>
>movlw 1
>subwf low,f
>movlw 0
>SKPC
>movlw 1
>subwf mid,f
>SKPC
>decf hi,f
>
>Any improvements on this?
>
>Thanks,
>Bob
>