On Tue, 5 Oct 1999, Ryan Miller wrote:

> Just out of curiosity, if you're using an 18C (or 17C) part,
> why wouldn't you use the CPFSEQ, CPFSLT, or CPFSGT
> mnemonics?

Hmmm. That IS a good question. The answer: I totally forgot about them!

Now the challenge, how would you use these for an efficient 16 bit
comparison?

Say

char compare(unsigned int a, unsigned int b)
{

 if(a<b)
   {
     a is less than b
   }
 else
   {
     a is greater than or equal to b
   }
}


  movf    b_hi,w
  cpfslt  a_hi
   bra    a_is_ge_b
  movf    b_lo,w
  cpfslt  a_lo
   bra    a_is_ge_b
a_is_lt_b
  ...


a_is_ge_b
  ...


But this can be made faster by using subtracts:

   movf   b_lo,w
   subwf  a_lo,w
   movf   b_hi,w
   subwfc a_hi,w
   bnc    ...      (or bc ...)

Any ideas?

Scott