Post by thread:[PIC]:Program memory subroutine tables

In a LED flasher project I did a while ago I used something like this : -a sequence variable held which sequence the PIC should play then : select_seq: ; subroutine bcf STATUS, C rlf seq, w addwf PCL, f call seq1 return call seq2 return call seq3 return ... Is there a more compact way to do something like this? (less program memory used? Here I need 2*sequences for this). ===== ing. Andrei Boros Centrul pt. Tehnologia Informatiei Societatea Romana de Radiodifuziune __________________________________________________ Do You Yahoo!? Send FREE Valentine eCards with Yahoo! Greetings! http://greetings.yahoo.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Yes. Use retlw. Watch out for program memory page breaks though. I'm not 100% shure you can use addwf on PCL, but some of the others will point that out if not. select_seq: ; subroutine bcf STATUS, C addwf PCL, f retlw seq1 retlw seq2 retlw seq3 {Original Message removed}

> In a LED flasher project I did a while ago I used something like this : > > -a sequence variable held which sequence the PIC should play > then : > > select_seq: ; subroutine > bcf STATUS, C > rlf seq, w > addwf PCL, f > call seq1 > return > call seq2 > return > call seq3 > return > ... > > Is there a more compact way to do something like this? (less program > memory used? Here I need 2*sequences for this). How about this... start: ;the nops are included to enable me to see where clrf seq ;the program goes when simulated in mplab nop nop nop loop: nop nop call select_seq movwf seq nop goto loop select_seq: ; subroutine movf seq,w addwf PCL, f goto seq1 goto seq2 goto seq3 goto seq4 seq1: nop nop retlw 0x01 seq2: nop nop retlw 0x02 seq3: nop nop retlw 0x03 seq4: nop nop retlw 0x00 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

--- Claudio Tagliola <spam_OUTcptagliolaTakeThisOuTCHELLO.NL> wrote: > Yes. Use retlw. Watch out for program memory page breaks though. I'm > not > 100% shure you can use addwf on PCL, but some of the others will > point > that out if not. seq1, seq2, seq3 are program memory pointers, larger then the 8bit wide w. They represent locations of subroutines one of which I have to call depending on the value of variable seq. {Quote hidden}> -a sequence variable held which sequence the PIC should play then : > > select_seq: ; subroutine > bcf STATUS, C > rlf seq, w > addwf PCL, f > call seq1 > return > call seq2 > return > call seq3 > return > ... > > Is there a more compact way to do something like this? (less program > memory used? Here I need 2*sequences for this). ===== ing. Andrei Boros Centrul pt. Tehnologia Informatiei Societatea Romana de Radiodifuziune __________________________________________________ Do You Yahoo!? Send FREE Valentine eCards with Yahoo! Greetings! http://greetings.yahoo.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Wed, 13 Feb 2002 08:38:45 -0800, Bob Ammerman wrote: >select_seq: > movf seq,W > addwf PCL,F > goto seq1 > goto seq2 > goto seq3 > >The individual 'seqN' routines end up RETURNing for select_seq. > Good one, Bob. This not only saves a bit of code space but a stack level as well. While there may be other reasons to do so, the only reason I can think of to ever follow a call immediately with a return is for setting breakpoints during debugging. Regards, Bob -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.