Re: how to decide the value of SF

Phil Carmody wrote:
Sebastian Biallas <spamtrap@xxxxxxxxxx> writes:

Tim Roberts wrote:
spamtrap@xxxxxxxxxx wrote:
if sub ax,ax(two numbers compared,the resulst is neither a plus nor
a negative )
how to determine the value of SF?
0 is a positive number.
No. By the usual mathematical definition, 0 is neither positiv nor negative.

By the usual x86 definition, 0 is positive.

The SF is set iff the result is negative (i.e. the MSB is set). So if it
isn't set, all you know is that the number is non-negative. Non-negative
is not the same as positive.

--
Gruß,
Sebastian

.

Relevant Pages

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