On Sep 12, 2016, at 5:03 PM, qemu-devel-requ...@nongnu.org wrote:
Looks like the ISO from comment #4 (thanks for attaching that one!)
shows the correct behavior with up to date QEMU 2.7. Also, the
affected
softfloat code has been completely reworked in between (e.g. with
commit
cf67c6bad56d43e6d60), so I assume this has been fixed sometimes in the
past years.
** Changed in: qemu
Status: New => Fix Released
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https://bugs.launchpad.net/bugs/672934
Title:
FPU incorrect on Mac OS X
Status in QEMU:
Fix Released
Bug description:
I am using the 0.13.0 release version of QEMU on Mac OS X 10.6.4. I
work for a university and the affected guest OS is our own research
OS. I believe I found a bug in QEMU's FPU emulation, which only
triggers on the Mac. You can reproduce the problem by booting the
attached ISO image.
Investigating the problem, I found that the lua interpreter in our
loader component (called "ned") internally uses doubles to represent
all lua-numbers. These doubles are showing completely wrong
values on
QEMU/Mac, resulting in the lua code not processing properly.
I also attached a patch which fixes the problem for me. The attached
ZIP-file also contains "before" and "after" screenshots. Note that
booting the ISO on a real machine or on a Linux-QEMU always shows
the
correct "after" behavior. Only QEMU on the Mac exhibits the wrong
"before" behavior without my patch. The patch might break other
systems setting the CONFIG_BSD flag, so maybe the preprocessor
should
check for __APPLE__ instead to make the fix Mac-only.
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I have always suspected a FPU bug with qemu-system-ppc. Apple's audio
processing code uses floating point code a lot. As a possible result
the playback of audio on a Mac OS guest is very poor. Is this a
problem with certain floating point instructions? Also could you send
me the patch. I would like to test it. Thanks.
