This is the mail archive of the
glibc-bugs@sourceware.org
mailing list for the glibc project.
[Bug math/3268] fma for all targets without hardware fma instructions is incorrect.
- From: "sjmunroe at us dot ibm dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: 6 Feb 2007 16:30:08 -0000
- Subject: [Bug math/3268] fma for all targets without hardware fma instructions is incorrect.
- References: <20060926212234.3268.sjmunroe@us.ibm.com>
- Reply-to: sourceware-bugzilla at sourceware dot org
------- Additional Comments From sjmunroe at us dot ibm dot com 2007-02-06 16:30 -------
Yes what you suggest should work for the generic s_fmaf.c, but that is not the
current implmentation. Also fmasf4.c should be a little faster as it avoids some
of the more expensive intermediate conversions.
s_fma.c would be more problematic because it would require full IEEE quad and TF
type support. I believe that you youself pointed out that not all platforms
support IEEE quad/TF type, but those platforms still need fma() to work correctly.
That is why I reworked the patch to avoid internal use of TF typs and support
direct RAW/SEMIRAW/CANNONICAL conversion for the intermediate steps of the
soft-fp fma. Again fmadf4.c should be faster then the generic.
Yes in the long run we will need to address soft-fp fmal but that requires the
invention of "oct or long long double" format. Most platforms that need soft-fp
don't implement long double 128-bit so we stage that function.
But we have a fix for soft-fp float and double now. I don't see any reason to delay.
--
http://sourceware.org/bugzilla/show_bug.cgi?id=3268
------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.