Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!evax!cs4344af
From: cs4344af@evax.arl.utexas.edu (Fuzzy Fox)
Newsgroups: comp.sys.cbm
Subject: Re: Undocumented 6502/6510/8502 instructions?
Message-ID: <1990Nov17.185259.10564@evax.arl.utexas.edu>
Date: 17 Nov 90 18:52:59 GMT
References: <4125.27440883@cc.nu.oz.au> <1990Nov16.214729.27679@Neon.Stanford.EDU> <1990Nov17.163800.12713@funet.fi>
Organization: Computer Science Engineering Univ. of Texas at Arlington
Lines: 22

In article <1990Nov17.163800.12713@funet.fi> po87553@korppi.tut.fi (Pasi 'Albert' Ojala) writes:
>>I saw this, and wondered whether anyone had done the same for the 6510
>>and 8502.  Would these be the same?
>>					-Brian
>
>  These undocumented op-codes aren't the same. For example some programmers
>used these ml-commands in their games --> they crashed on c128..
>It's the same with 6502, op-codes do match, but undocumented commands do not.
>I have a documentation about 6510's op-codes (including 'undocumented' codes),
>so if you can't get it anywhere else, mail me.
>

The 6502, 6510, and 8502 are all internally the same as far as
instruction processing goes, so the illegal opcodes generate the same
effects on all three CPU's.  The reason that many games crashed on the
128 is that they would often accidentally twiddle some memory locations
that differ between the 64 and 128 (such as $D030, which does nothing on
the C64 and can switch to 2 MHz-no-video mode on the C128).

I believe I have a list of opcodes that were generated by an Apple
hacker on the Apple ][ (6502 processor).  I will attempt to locate them
and post them up here.