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Re: PPro patch #3
- To: law at cygnus dot com
- Subject: Re: PPro patch #3
- From: hjl at lucon dot org (H.J. Lu)
- Date: Fri, 5 Jun 1998 08:31:59 -0700 (PDT)
- Cc: egcs-patches at cygnus dot com
>
>
> In message <m0yhbje-000268C@ocean.lucon.org>you write:
> > Here is a patch to fix unordered comparison for PPro.
> >
> >
> > H.J.
> > ----
> > Tue May 19 06:51:19 1998 H.J. Lu (hjl@gnu.org)
> >
> > * config/i386/i386.c (notice_update_cc, output_float_compare):
> > Enable TARGET_CMOVE support.
> >
> > Mon May 11 08:04:17 1998 H.J. Lu (hjl@gnu.org)
> >
> > * config/i386/i386.c (output_float_compare): Fix the unordered
> > comparison for IEEE math and CC_FCOMI.
> Exactly what problem is this patch trying to fix?
The testcase is in my previous email. But you need to enable CC_FCOMI
to see it.
>
> "Here is a patch to fix unordered comparison for PPro." tells me
> almost nothing.
>
Please get PPro/II reference manual and check out fcomi. You will see
PPro/II cannot handle unordered comparison directly which sets CC in a
way compatible with integer comparison. BTW, Jim may know it since it
is he who disabled fcomi, which hides the bug.
--
H.J. Lu (hjl@gnu.org)