On Wed, 18 Apr 2001, Bob Ammerman wrote:

> Scott Dattalo [almost] brilliantly stated:
>
> That B * 255 can be computed by:
>
> >
> >     decf   B,w
> >     movwf  PRODUCT_HI
> >     xorlw  0xff
> >     movwf  PRODUCT_LO
> >
>
> Except, what happens if B == 0?
>
> decf B,W        ; W = 0xFF
> movwf        PRODUCT_HI     ; Product HI = 255
> xorlw    0xFF    ;W = 0
> movwf        PRODUCT_LO    ; Product lo = 0
>
> Not such a good thing.
>
> 0 * 255 is not == 65280 (0xFF00)
>

Yeah, I saw that. However, the original snippet suffers from the same
problem. But you could follow it with:

    skpnz
     clrf  PRODUCT_HI

Scott

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