glibc/sysdeps/arm/fedisblxcpt.c
Wilco 001f7b773c Speed up the ARM fenv implementation by avoiding unnecessary FPSCR
writes if the FPSCR remains unchanged.

2014-06-24  Wilco  <wdijkstr@arm.com>

	* sysdeps/arm/fclrexcpt.c (feclearexcept):
	Optimize to avoid unnecessary FPSCR writes.
	* sysdeps/arm/fedisblxcpt.c (fedisableexcept): Likewise.
	* sysdeps/arm/feenablxcpt.c (feenableexcept): Likewise.
	* sysdeps/arm/fsetexcptflg.c (fesetexceptflag): Likewise.
	* sysdeps/arm/setfpucw.c (__setfpucw): Likewise.
2014-06-24 12:04:27 +00:00

44 lines
1.3 KiB
C

/* Disable floating-point exceptions.
Copyright (C) 2001-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Philip Blundell <philb@gnu.org>, 2001.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <fpu_control.h>
#include <arm-features.h>
int
fedisableexcept (int excepts)
{
fpu_control_t fpscr, new_fpscr;
/* Fail if a VFP unit isn't present. */
if (!ARM_HAVE_VFP)
return -1;
_FPU_GETCW (fpscr);
excepts &= FE_ALL_EXCEPT;
new_fpscr = fpscr & ~(excepts << FE_EXCEPT_SHIFT);
/* Write new exceptions if changed. */
if (new_fpscr != fpscr)
_FPU_SETCW (new_fpscr);
return (fpscr >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;
}