Hi again,

I had checked your code, seems that there are two errors on the result
and may not work.

regards,
Reggie

Dmitry Kiryashov wrote:
>
> movfw   Cy      ;carry cell
> xorlw   K       ;constant or second var
> iorwf   Cy,f    ;invertion mask
> xorwf   R,f     ;result
> andwf   R,w     ;pre-carry
> xorwf   Cy,f    lfinal true carry
>
> -->
> +--------+-------------+
> | R K Cy | w Cy R w Cy |
> +--------+-------------+
> | 0 0 0  | 0 0  0 0 0  |
> | 0 0 1  | 1 1  1 1 0  |
> | 0 1 0  | 1 1  1 1 0  |final Cy should be 1 because W=1 and Cy=0
> | 0 1 1  | 0 1  0 0 1  |
> | 1 0 0  | 0 0  1 0 0  |
> | 1 0 1  | 1 1  0 0 1  |
> | 1 1 0  | 1 1  0 0 1  |also Cy should be 0 because W=0 and Cy=0
> | 1 1 1  | 0 1  1 0 1  |
> +--------+-------------+