ANE (fwd)

From: Marko Mäkelä (
Date: 1998-07-23 14:14:02

This was sent to the plus4 list.  Previously I knew (from Andreas Boose)
that the $8B opcode (or was it $AB, anyway the opcode with 
non-deterministic behaviour) behaves differently if DMA takes place
between the opcode fetch and the parameter fetch.

---------- Forwarded message ----------
Date: Thu, 23 Jul 1998 13:55:15 +0200
From: Tibor Biczo <>
Subject: ANE

Hi there,

I was playing a bit with ANE opcode $8B, and found out,
that the result is also dependant on the instruction which
was executed before it! I had the instruction execute
on a fixed raster dot, and the result was mostly stable
(Certain bits sometimes seemed to be not stable), and
if I changed the instruction before it so that the registers
remained the same (like changing an STA to an STX) the result
of the instruction changed. I haven't gone into details, much
This was on a 8501, and I wonder if one of the C64 owner would
check this on the 6502?

Tibor Biczo / Crown of GOTU

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