[Qemu-devel] [Bug 672934] Re: FPU incorrect on Mac OS X

[Samuel Bronson]

** Tags added: mac

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https://bugs.launchpad.net/bugs/672934

Title:
  FPU incorrect on Mac OS X

Status in QEMU:
  New

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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