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MEGA65 / mega65-user-guide

MEGA65 User Guide
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Document VIC-IV errata register #583

Closed dansanderson closed 4 months ago

dansanderson commented 7 months ago

The latest dev core has a new VIC-IV feature where two changes in behavior that are considered fixes to VIC-III design flaws are behind an "errata" register. Let's make sure the register and the complete list of errata levels gets a place in the manual.

$D08F is the 8-bit errata register. 0 = full compatibility with C65 prototypes. 1 = VIC III D016 Delta fix. 2 = 1 + char attr fix. 255 would be current and all future fixes.

There's also D07A bit 5, which is equivalent to (and synchronous with) D08F=0 or 255. I believe this only existed in dev cores, but we're keeping it just in case someone was using it. We might as well mention it in the docs near a description of D08F.

dansanderson commented 4 months ago

This was done a while ago.