[CCTECH] Interesting tidbit on 6502

From: Sipke de Wal <sipke_at_wxs.nl>
Date: Fri Jun 7 13:34:51 2002

Problem with the 6502 is that different versions
from different manufacturers had different
undocumented instructions. So for the general
public this was not much of a boon ....

The Z80 situation was much better

Also the 65C02 (the special CMOS version)
als was more reliable in this respect

Sipke de Wal
-----------------------------------------
http://xgistor.ath.cx
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----- Original Message -----
From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
To: <cctalk_at_classiccmp.org>
Sent: Friday, June 07, 2002 8:03 PM
Subject: Re: [CCTECH] Interesting tidbit on 6502


<snip>
>
> Many processors (and other chips for
> that matter) have undocumented
> instructions used for factory testing.
>
>
> -tony
>
Received on Fri Jun 07 2002 - 13:34:51 BST