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> From: Andrew Warren <fastfwd@IX.NETCOM.COM>

> > How really the computer computes a SUB operation? (Using TWO'S
> > COMPLEMENT???)
>
>     Yes, mIGUEL, that's how the PIC does it; if you look at the
>     table of instructions in the PIC datasheets, you'll see that
>     SUBWF is computed by taking the two's complement of W, then
>     adding it to F.


The actual Subtract calculation on a PIC is

    result = arg + ~W + 1

The calculation is done in the above order. (The carry is set
on the results of the last add)

Walter Banks