Re. imsai 2 (OT)

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Tue Aug 24 15:58:47 1999

> > and the vendors would make sure they were there.
>
> This is fine if you're a large company and can specify the 'undocumented'
> behaviour of a chip. For a one-off hacker like me, it's a little more
> dangerous.

You werent reading. Also you missed that due to popular request for 8085
and z80 it's pretty much if they aint there it must not be a 8085 or z80!
They are defacto supported as a result and a hobbiest can rely on their
presence.


> AFAIK, all Z80s did the same thing with undocumented opcodes, and it was
> safe to rely on them. But I've met devices (not CPUs specifically) where
> later/second-source versions have had different behaviour under
> 'undocumented' conditions, so I learnt the hard way to be careful.

My reference for 8085 and z80 is however limited to them but, for all
vendors of those parts (and versions thereof) that I know of it's true.
Timing differnces are more common.

allison
Received on Tue Aug 24 1999 - 15:58:47 BST

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