Sergio Masci <piclist@mit.edu> wrote:

> > It seems as though two instructions (BTFSC RA3 / BSF RB4) would
> > suffice... What three instructions are generated by XCSB?
> 
> Yes you are right two machine instructions would be better than three,
> but the point is that three is still increadibly good going when you
> concider the amount of source that has been condensed into these three
> instructions.
> 
> The three instructions generated by xcsb are:
> 
>    btfss   5,3
>    goto   x_else_0000
>    bsf     6,4
> x_else_0000

Sergio:

I'm sorry if my comment was misunderstood... I'm aware of the point 
you were making; I asked about the three instructions only because I 
was curious.  

Your compiler's ability to understand what the function parameters 
actually mean is impressive; I assume that you'll eventually add some 
peephole optimization as a final step, to clean up simple cases like 
this one.  

By the way, do both of these also generate three instructions?  

    proc main()
      if test_bit(RA3) == 0 then    // was originally "== 1"
        set_bit(RB4)
      endif

    proc main()
      if test_bit(RA3) == 1 then
        {}
      else
        set_bit(RB4)
      endif

-Andy

=== Andrew Warren -- aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
=== 
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

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