Re: A83: Atten: James Matthews


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Re: A83: Atten: James Matthews




Now let's get this straight once and for all:

!--->>> *The cp instruction performs a temporary subtraction* <<<---!

And negative numbers are expressed like this; -1 is what you get if you
subtract 1 from zero (ffh), -2 is what you get if you subtract 2 from zero
(feh) and so on.

Linus

On 08-Oct-98, Bruce Link wrote:

>I read your little tutorial on jp jr and call... very enlightening.. except
>for one thing..
>the occurrences used with jp, mainly m.

>Minus: meaning (I assume) less than zero. Not less the compared number.
>But since the accumulator is only 8 bit.. how can you have a negative number?
>Or is it simply a case of it being less than?

>I have also been using the 'carry' command after jump and have found that
>it works well as a 'less than' statement conversely I have been increasing
>the accumulator and using the nc statement as a 'greater than' statement
>with a good deal of success. Any comments on these practices?

>Thanx
>Bruce



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