From: Bruno Haible <1912934@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1912934] [NEW] QEMU emulation of fmadds instruction on powerpc64le is buggy
Date: Sun, 24 Jan 2021 08:40:41 -0000 [thread overview]
Message-ID: <161147764119.28788.10484645020687886149.malonedeb@soybean.canonical.com> (raw)
Public bug reported:
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 ).
** Affects: qemu
Importance: Undecided
Status: New
** Attachment added: "Test case"
https://bugs.launchpad.net/bugs/1912934/+attachment/5456225/+files/test-fmadds.c
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
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 ).
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912934/+subscriptions
next reply other threads:[~2021-01-24 8:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-24 8:40 Bruno Haible [this message]
2021-05-12 18:11 ` [Bug 1912934] Re: QEMU emulation of fmadds instruction on powerpc64le is buggy Thomas Huth
2021-05-14 19:55 ` Bruno Haible
2021-05-15 10:53 ` Thomas Huth
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=161147764119.28788.10484645020687886149.malonedeb@soybean.canonical.com \
--to=1912934@bugs.launchpad.net \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).