New subject: Amiga 2000HD Hard disk

17 Apr 1999

The 6502 series ahd all sorts of undocumented opcodes and they tended to 
change with later versions.

<THe 65xx stuff is quite known, but what has been new to my ears are the
<8085 'hidden' operations.

Those were more useful as the 8085 had some rather open holes in the 
instruction set.  The z80 also had a raft of them all commonly supported
though officially unofficial. and none were compatable with the 8085 hidden 
ops (in either direction).

Allison

z80 timing... 6502 timing