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Optimize fesetenv 

Improve fesetenv to use an optimized implementation similar to
feupdateenv.

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

	* sysdeps/arm/fesetenv.c (fesetenv): Optimize implementation.
This commit is contained in:
Wilco 2014-06-24 15:05:23 +00:00
parent b5570d92d6
commit b8c005732e
2 changed files with 27 additions and 18 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
2014-06-24 Wilco <wdijkstr@arm.com>
* sysdeps/arm/fesetenv.c (fesetenv): Optimize implementation.
2014-06-24 Wilco <wdijkstr@arm.com> 2014-06-24 Wilco <wdijkstr@arm.com>
* sysdeps/arm/fpu_control.h (_FPU_MASK_RM): Define. * sysdeps/arm/fpu_control.h (_FPU_MASK_RM): Define.

41
sysdeps/arm/fesetenv.c
View File

@ -17,14 +17,13 @@
<http://www.gnu.org/licenses/>. */ <http://www.gnu.org/licenses/>. */
#include <fenv.h> #include <fenv.h>
#include <fpu_control.h>
#include <arm-features.h> #include <arm-features.h>
int int
fesetenv (const fenv_t *envp) fesetenv (const fenv_t *envp)
{ {
fpu_control_t fpscr; fpu_control_t fpscr, new_fpscr, updated_fpscr;
/* Fail if a VFP unit isn't present. */ /* Fail if a VFP unit isn't present. */
if (!ARM_HAVE_VFP) if (!ARM_HAVE_VFP)
@ -32,25 +31,31 @@ fesetenv (const fenv_t *envp)
_FPU_GETCW (fpscr); _FPU_GETCW (fpscr);
/* Preserve the reserved FPSCR flags. */ if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
fpscr &= _FPU_RESERVED;
if (envp == FE_DFL_ENV)
fpscr |= _FPU_DEFAULT;
else if (envp == FE_NOMASK_ENV)
fpscr |= _FPU_IEEE;
else
fpscr |= envp->__cw & ~_FPU_RESERVED;
_FPU_SETCW (fpscr);
if (envp == FE_NOMASK_ENV)
{ {
/* The new FPSCR is valid, so don't merge the reserved flags. */
new_fpscr = envp->__cw;
/* Write new FPSCR if different (ignoring NZCV flags). */
if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0)
_FPU_SETCW (new_fpscr);
return 0;
}
/* Preserve the reserved FPSCR flags. */
new_fpscr = fpscr & _FPU_RESERVED;
new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE;
if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0)
{
_FPU_SETCW (new_fpscr);
/* Not all VFP architectures support trapping exceptions, so /* Not all VFP architectures support trapping exceptions, so
test whether the relevant bits were set and fail if not. */ test whether the relevant bits were set and fail if not. */
_FPU_GETCW (fpscr); _FPU_GETCW (updated_fpscr);
if ((fpscr & _FPU_IEEE) != _FPU_IEEE)
return 1; return new_fpscr & ~updated_fpscr;
} }
return 0; return 0;