Regulus Berdin wrote:

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

Again I see no problem there. ;)

1. R=0 K=1 Cy=0

movfw   Cy      ;W=0
xorlw   K       ;W=1
iorwf   Cy,f    ;Cy=1
xorwf   R,f     ;R=1
andwf   R,w     ;W=1
xorwf   Cy,f    ;Cy=0

0 + 1 + 0 = 01b. Cy=0 R=1. Isn't it ? ;)

2. R=1 K=1 Cy=0

movfw   Cy      ;W=0
xorlw   K       ;W=1
iorwf   Cy,f    ;Cy=1
xorwf   R,f     ;R=0
andwf   R,w     ;W=0
xorwf   Cy,f    ;Cy=1

1 + 1 + 0 = 10b. Cy=1 R=0. The questions ? ;)

Reggie there are no errors in this code. Please apply
efforts to reduce it not to find an errors inside it.

WBR Dmitry.

> > 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  |
> > +--------+-------------+