Subroutine placement - must they come first?

[mister_e]

One good thing to remember about asm DATA, DA, DT...

Recently I've messed a lot with the Nokia GLCD thing and while I added Strings, some could not be properly displayed, code went to lalaLand. The reason is like Bruce said... page boundary. In the end my macro just needed a simple modification... from something like

MyWhateverString Macro Str
           local STRStart, STREnd
           GOTO STREnd
STRStart
           DT Str
STREnd
           MOVE?CW STRStart, _WhateverAddrVar
           L?CALL _MainSub
           ENDM

To

MyWhateverString Macro Str
           local STRStart, STREnd
           L?GOTO STREnd
STRStart
           DT Str
STREnd
           MOVE?CW STRStart, _WhateverAddrVar
           L?CALL _MainSub
      ENDM

problem solved

[Archangel]

One good thing to remember about asm DATA, DA, DT...

Recently I've messed a lot with the Nokia GLCD thing and while I added Strings, some could not be properly displayed, code went to lalaLand.

Oh Steve, that was Your code I saw . . .

[mister_e]

A snip of...few hundred lines....

[BrianT]

My ignorance is on clear display here so please be gentle.
I have a system of two PIC16F88 and three 18F4620 which all chatter amongst themselves over a multiwire parallel bus. Some of the code takes up over 63000 bytes on a PIC 18F4620.
Currently all the subroutines are placed after the hardware and variable declarations. I would like to have the subroutines at the bottom of the code if possible for simpler reading.

I recall some earlier (PBP2.xx?) comments that subroutines should be at the top of the program but is there any more explicit advise for the 16F88 or the 18F4620. Bruce's comments pass over my head.

Cheers
BrianT

[Charlie]

You can put subroutines anywhere you like and PBP worries about page swaps for you. If, however, you have real time or compiled code size issues, putting them at the beginning can help optimize. There are also special issues when crossing page boundaries that PBP *usually" takes care of - a notable exception is mentioned above.

I always put my subroutines at the end for readability. in 99% of cases this is fine.
These days I like to use 18F parts which tend to have a better sense of humour about these things, as well as usually being faster and having more memory. (at slightly highter cost)