On Fri, 2005-07-15 at 22:26 -0700, Andrew Warren wrote:
Scott Dattalo <piclist@mit.edu> wrote:
>
> > I don't know what I was thinking earlier - I guess I've been
> > smoking too many virtual functions here lately!
>
> Dude:
>
> Assembly = the win.  C++ = the suck.
>

:)

> P.S. Here's some better commenting (and more-descriptive register
> naming):

<snip>

And here's a brute-force version that is a little faster, but takes more
instructions:

23 instructions,   10-15 Cycles - average 13 (which is one cycle too many
- there must be a way to get this to 12 cycles!)

   movf  REGA,W
   subwf REGB,W   ; W=B-A
   skpc
    goto L_A_GT_B

   ; B>=A

   movf  REGA,W
   subwf REGC,W   ; W=C-A
   skpc
    goto L_AisMedian ; B>=A>=C

   ; B>=A, C>A

   movf  REGB,W
   subwf REGC,W   ; W=C-B
   movf  REGC,W   ; Assume C is the median
   skpnc
L_BisMedian:
    movf REGB,W   ;
   goto  done

L_A_GT_B:
   ; A>B

   movf  REGB,W
   subwf REGC,W   ; W=C-B
   skpc
    goto L_BisMedian ; A>B>C

   ; A>B, C>=B

   movf  REGA,W
   subwf REGC,W   ; W=C-A
   movf  REGC,W
   skpnc
L_AisMedian:
    movf REGA,W   ; C>A>B

done:


Scott
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