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[Qemu-devel] Emulation differences, qemu-system-x86_64 vs Athlon64

From: Julian Seward
Subject: [Qemu-devel] Emulation differences, qemu-system-x86_64 vs Athlon64
Date: Wed, 12 Apr 2006 13:08:00 +0100
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Recently I've been playing with CVS qemu-system (softmmu) on amd64
and had some stability problems.  I decided to run Valgrind's amd64
instruction-set tests (derived from qemu's) to see if they picked up
anything.  Resulting diffs are attached.

There are a bunch of differences for the C flag for rotates
(rol/ror) by multiples of the word size.  I don't think these
are significant, but who knows.

Perhaps more worryingly are the 20 or so lines at the bottom
of the diff.  These I believe are for double-to-int/short
conversions for a value which is out of range for an int/short;
the hardware produces 0x80000000/0x8000 respectively, which is
the "integer indefinite"; QEMU produces zero.  I can imagine some
obscure routine somewhere checking for integer indefinite after
conversion and being confused as a result.


Attachment: diffs-qemu-vs-Athlon64.txt.bz2
Description: BZip2 compressed data

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