Fast bitwise AND?  How many points for:

        bcf     C, bit_c
        btfss A, bit_a
        goto    BitwiseAndEnd:
        btfss   B, bit_b
        goto  BitwiseAndEnd:
        bsf     C, bit_c
BitwiseAndEnd:


-Ed VanderPloeg.

At 12:22 PM 9/2/97 -0800, you wrote:
>
>How fast can you logically AND two bits?
>
>Given:
> bit_a  of register A
> bit_b  of register B
> bit_c  of register C
>
>The goal in C parlance is:
>
>  C.bit_c = A.bit_a & B.bot_b;
>
>
>And just so it's clear, here's some sluggish PIC code that does
>the job:
>
>        CLRW
>        BTFSC   A,bit_a
>         MOVLW  1
>        BTFSC   B,bit_b
>         CLRW
>        BCF     C,bit_c
>        IORLW   0
>        SKPZ
>         BSF    C,bit_c
>
>9 unbearably long cycles and trashes W. Last week I placed too much
>emphasis on preserving W. This week the emphasis is on speeeed.
>
>So here are how the points are to be tallied:
>
>   1) Size: 2*(6 - # of execution cycles)
>   2) Isosynchonous: 3 points
>   3) Preserves W: 2 points
>   4) Preserves reg A and B: 1 point
>
>The example slug scores: 2*(6-9) + 3 + 0 + 1 = -2
>
>My pre-Payson/Keitz solution is worth 10 points.
>hint:   x & y = ~(~x | ~y)
>
>
>Scott
>--
>                                       __o
>  I still buy pizza instead of gas.    \<
>                                    (*)/(*)
>
>
>