Re: [stella] 65xx Questions

Subject: Re: [stella] 65xx Questions
From: Thomas Jentzsch <tjentzsch@xxxxxx>
Date: Mon, 8 Jul 2002 20:42:11 +0200
At 08.07.2002, 18:20, Paul Slocum wrote:
> 1) What is the difference between overflow and carry?

An overflow is useful when you are working with *signed* integers. It's
working like the carry.

If you e.g. add 50 to 100 you get an overflow because 150 is larger than
the maximum positive signed value. Other examples that cause an overflow:
-50 - 100
-50 + -100
100 - -50

> 2) What are some common situations where EOR is useful?

EOR is also very useful if you want to change single bits inside a byte.

And you can also use EOR, BEQ/BNE instead of CMP, BEQ/BNE if you want a
0 inside the accumulator.

Have fun!
Thomas Jentzsch         | *** Every bit is sacred ! ***
tjentzsch at web dot de |

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