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Bug in DAA #6

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fordp2002 opened this issue Feb 23, 2017 · 1 comment

fordp2002 commented Feb 23, 2017

See hoglet67/PiTubeDirect#42 for more information!

hoglet67 commented Feb 24, 2017 •

edited

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Thanks Ford for creating this issue.

Specifically. these are the 6 cases where Zet incorrectly sets the carry flag:

cf=0 af=1 al=  0 : cfout=1 afout=1 alout=  6
cf=0 af=1 al=  1 : cfout=1 afout=1 alout=  7
cf=0 af=1 al=  2 : cfout=1 afout=1 alout=  8
cf=0 af=1 al=  3 : cfout=1 afout=1 alout=  9
cf=0 af=1 al=  4 : cfout=1 afout=1 alout=  A
cf=0 af=1 al=  5 : cfout=1 afout=1 alout=  B

Some context: We're using Zet in the Matchbox Co Processor for the Beeb to re-implement Acorns 80186 Co Processor:
https://github.com/hoglet67/CoPro6502/wiki

Over the last couple of years I've made several other bug fixes, which you can see in the history here:
https://github.com/hoglet67/CoPro6502/commits/master/src/zet

There's still at least one more latent bug, as the debugger D86 just hangs on startup. Not had a chance to look into this.

Thanks for all your work on Zet, much appreciated.

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