On Wed, May 25, 2005 at 04:03:50PM +0100, Ian Chapman wrote:
> Wouter van Ooijen <wouter@voti.nl> wrote:
> >Challenge (intermediate): write a JUMP <LABEL> macro for the 14-bit core
> >PICs that jumps to the target address. The macro must handle code
> >paging, hence it will in general expand to more than one instruction.
> >When preceded by a skip instruction (for instance btfss or skpz) the
> >JUMP macro must behave as a naive user would expect: the jump must not
> >be taken, execution must proceed with the instruction after the JUMP.
> 
> I'd suggest something like this:
[...]
> It's a bit ugly, though.  The macro consumes 3-5 program words (*) each
> time it is invoked, and the execution time is 4-6 cycles (*) if the jump
> is taken and 3 cycles if it is skipped (excluding the skip instruction).
> 
> (*) depending on the number of the code pages in the device
> 
> Any better offers?

It's not quite following the rules, but how about:

nojump	MACRO	target
	LOCAL	skipped
	GOTO	skipped
	PAGESEL target
	GOTO 	target
skipped:

Then you have to reverse the skip condition, but you lose one extra
goto.

Chris
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