Re: A85: Pixel mover
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Re: A85: Pixel mover
On Tue, 11 Nov 1997 21:26:23 -0500 egillespie@juno.com (Erik L Gillespie)
writes:
>ok, i understand why it subtracts 7 from a but how
>does the calculator know when you want to subtract
>and when you want to add? for instance would this
>statement:
>
>add a, $B3
>
>add 179 to a or would it subtract 77 from a?
>(might not be the right #s but i think you get the idea)
They are basically the same, but the major difference is the way the
carry bit is affected.
add a, $B3 would add 179, but if the number in a was larger than 76 it
would be as if 77 had been subtracted and the carry bit was set. It would
still actually add.
Sincerely,
The Unibomer
Jared Ivey
Unibomer@Juno.com
http://www.geocities.com/SiliconValley/Vista/7342
"The goal of Computer Science is to build something that will last at
least until we've finished building it." -- Unknown
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