On Wed, 12 Apr 2000, Walter Banks wrote:

>
>   Compilers can generate code sequences that are extremely difficult
>   to maintain in assembler. For example, on the PIC's using the lsb of the
>   PC to implement an unconditional skip the generated code sequence is
>   address dependent..

Walter,

Could you give us some examples where this may be useful? The only situation
that I can imagine is link-time optimization. For example, if you created a
library that supports a mix of features, then you could select which features
are enabled simply based on where the code is located.


start:
    btfsc  pcl,0
     goto  feature1

feature2:
     ...

If the address of start is even, then feature2 is implemented otherwise feature1
is implemented. This also saves having to pass a parameter to the library
function being implemented (in other words, you could achieve the same
functionality by testing a passed parameter).

Now if the code with which you are linking is 'exposed' (as opposed to buried in
some library), then the same effect could be achieved with macros and
conditional assembly too. So us asm only guys and gal, wouldn't benefit too
much.

Scott