Re: [Sdcc-user] inline asm with pic14 port

[Scott D. <sc...@da...>]

On Tue, 20 May 2003, Greg Hill wrote:

> I'm trying to get some inline assembly into a C file (it's a semi-precise
> time delay loop). Here's my sdcc version:
> SDCC : mcs51/gbz80/z80/avr/ds390/pic14/pic16/TININative/xa51/ds400 2.3.5
> (May 18 2003) (UNIX)
> 
> It seems that the '$' character I've used in my label in the inline asm is
> confusing the peephole optimizer. (I used the numeric label with $ at the
> end because it's suggested in the current sdccman.pdf). Here's the output
> I get:
> gregh: ~/projects> sdcc -mpic14 -pp16f628 second.c
> Processor: p16f628
> Error while parsing peep rules (check peeph.def)
> Line:       goto 00001$
> Token: '$'
> 
> and here's the code for the function with the inline asm:
> void delay500us(unsigned char count) {
>   for(; count > 0; count--) {
>     _asm
>       movlw  0xA6
>       movwf  _delay
> 00001$:
>       decfsz _delay,f
>       goto   00001$
>       _endasm;
>   }
> }

What happens if you do this:

     _asm
      movlw  0xA6
      movwf  _delay
 L1:  decfsz _delay,f
      goto   L1
     _endasm;


The "assembler" for the inline assembly is a really simple 1-line 
assembler. The label must occur on the same line of the instruction to 
which it refers. The '$' is not a supported character. In fact in gpasm, 
'$' is the "current address" operator. E.g. one can write goto $+2 to 
branch 2 instructions beyond the address at which the goto is located.

Scott