[Bug 1912934] Re: QEMU emulation of fmadds instruction on powerpc64le is buggy

[Bruno Haible]

The situation is still the same in QEMU 6.0.0.

$ powerpc64le-linux-gnu-gcc-5 test-fmadds.c -static
$ ~/inst-qemu/6.0.0/bin/qemu-ppc64le ./a.out ; echo $?
32


** Changed in: qemu
       Status: Incomplete => New

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https://bugs.launchpad.net/bugs/1912934

Title:
  QEMU emulation of fmadds instruction on powerpc64le is buggy

Status in QEMU:
  New

Bug description:
  The attached program test-fmadds.c tests the fmadds instruction on
  powerpc64le.

  Result on real hardware (POWER8E processor):
  $ ./a.out ; echo $?
  0

  Result in Alpine Linux 3.13/powerpcle, emulated by QEMU 5.0.0 on Ubuntu 16.04:
  $ ./a.out ; echo $?
  32

  Result in Debian 8.6.0/ppc64el, emulated by QEMU 2.9.0 on Ubuntu 16.04:
  $ ./a.out ; echo $?
  32

  Through 'nm --dynamic qemu-system-ppc64 | grep fma' I can see that
  QEMU is NOT using the fmaf() or fma() function from the host system's
  libc; this function is working fine in glibc of the host system (see
  https://www.gnu.org/software/gnulib/manual/html_node/fmaf.html ).

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