Re: [stella] 6507 secrets

Subject: Re: [stella] 6507 secrets
From: jimn8@xxxxxxxxxx (Jim Nitchals)
Date: Tue, 9 Sep 1997 13:32:43 -0700 (PDT)
> It seems that the 6502 has a lot of undocumented instructions.
> And the 6507?! :-O

The 6507 is just a 6502 in cost-reduced packaging.  The undocumented
instructions will work the same.  Sure, they'd screw up an emulator
and possibly redesigned 2600's like the TV-Boy, as later 6502 designs
made use of the opcode space for other purposes.

A quick rule of thumb is that opcodes of x3 do a x2 followed by x1.
x7 does x6 followed by x5.  It's probably not worth your time messing
with them until you've mastered vanilla 6502 to the limits  ;)

- Jim

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