[sebhc] HASL-8 Bug/Corruption?

Lee Hart leeahart at earthlink.net
Thu May 13 10:23:14 CDT 2004


>>...however you can't always just Ignore a bad opcode - $DD ..
>> decodes it as a CALL,

Steven Parker wrote:
> Neat, I didn't remember that.  I'm guessing that any 11xx1101 would
> be a CALL, and any 1100x011 would be a JMP, and 110x1001 would be
> RET (and of course, all 00xxx000 are NOP). I suppose for accurate
> emulation all of those would have to be handled.

Careful; while they may be "don't cares" for the 8080, they are NOT for
the Z80 or 8085! You would wind up with code that wouldn't work on an
H89 or Z-100. And it was pretty common to put a Z80 CPU board in the H8.

>> NOW - If only I can get my hands on the disk controller specs!
>> Also, anyone got H-37/47/67 manuals?

I have these for the H89, but not the H8. They "ought" to be the same,
since the same code generally works in both.
-- 
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart  814 8th Ave N  Sartell MN 56377  leeahart_at_earthlink.net


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