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Re: [PATCH] [AArch64] Suppress unnecessary FPSR and FPCR writes
- From: Marcus Shawcroft <marcus dot shawcroft at gmail dot com>
- To: ian dot bolton at arm dot com
- Cc: GNU C Library <libc-alpha at sourceware dot org>
- Date: Thu, 24 Apr 2014 07:28:42 +0100
- Subject: Re: [PATCH] [AArch64] Suppress unnecessary FPSR and FPCR writes
- Authentication-results: sourceware.org; auth=none
- References: <20140423235146 dot GA20028 at e104535-lin dot arm dot com>
On 24 April 2014 00:51, Ian Bolton <ian.bolton@arm.com> wrote:
> Writes to fpsr and fpcr are expensive. This patch adds checks before each
> write to ensure we only write new values to them (as opposed to rewriting
> what's there).
>
> Tested with make check and make bench, with no regressions.
>
> OK for commit?
>
> Cheers,
> Ian
>
>
> 2014-04-24 Ian Bolton <ian.bolton@arm.com>
>
> * sysdeps/aarch64/fpu/fclrexcpt.c (feclearexcept): Don't write to
> fpsr if value didn't change.
> * sysdeps/aarch64/fpu/fedisblxcpt.c (fedisableexcept): Don't write
> to fpcr if value didn't change.
> * sysdeps/aarch64/fpu/feenablxcpt.c (feenableexcept): Likewise.
> * sysdeps/aarch64/fpu/feholdexcpt.c (feholdexcept): Don't write to
> fpsr or fpcr if value didn't change.
> * sysdeps/aarch64/fpu/fesetenv.c (fesetenv): Likewise.
> * sysdeps/aarch64/fpu/fesetround.c (fesetround): Don't write to
> fpcr if value didn't change.
> * sysdeps/aarch64/fpu/fsetexcptflg.c (fesetexceptflag): Don't write
> to fpsr if value didn't change.
OK, and committed.
/Marcus