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[PATCH 6/7] i386/x86_64: Optimize feholdexcept.
* sysdeps/i386/fpu/feholdexcpt.c (feholdexcept): Avoid the fldenv.
* sysdeps/x86_64/fpu/feholdexcpt.c (feholdexcept): Likewise.
---
sysdeps/i386/fpu/feholdexcpt.c | 17 ++++-------------
sysdeps/x86_64/fpu/feholdexcpt.c | 21 +++++++--------------
2 files changed, 11 insertions(+), 27 deletions(-)
diff --git a/sysdeps/i386/fpu/feholdexcpt.c b/sysdeps/i386/fpu/feholdexcpt.c
index a09d45e..49f7ced 100644
--- a/sysdeps/i386/fpu/feholdexcpt.c
+++ b/sysdeps/i386/fpu/feholdexcpt.c
@@ -1,6 +1,5 @@
/* Store current floating-point environment and clear exceptions.
- Copyright (C) 1997, 1999, 2003, 2004, 2005, 2007
- Free Software Foundation, Inc.
+ Copyright (C) 1997-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
@@ -28,17 +27,9 @@ feholdexcept (fenv_t *envp)
{
fenv_t temp;
- /* Store the environment. */
- __asm__ ("fnstenv %0" : "=m" (temp));
- *envp = temp;
-
- /* Now set all exceptions to non-stop. */
- temp.__control_word |= 0x3f;
-
- /* And clear all exceptions. */
- temp.__status_word &= ~0x3f;
-
- __asm__ ("fldenv %0" : : "m" (temp));
+ /* Store the environment. Recall that fnstenv has a side effect of
+ masking all exceptions. Then clear all exceptions. */
+ __asm__ volatile ("fnstenv %0; fnclex" : "=m" (*envp));
/* If the CPU supports SSE we set the MXCSR as well. */
if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
diff --git a/sysdeps/x86_64/fpu/feholdexcpt.c b/sysdeps/x86_64/fpu/feholdexcpt.c
index b547b34..b380479 100644
--- a/sysdeps/x86_64/fpu/feholdexcpt.c
+++ b/sysdeps/x86_64/fpu/feholdexcpt.c
@@ -1,5 +1,5 @@
/* Store current floating-point environment and clear exceptions.
- Copyright (C) 2001, 2005, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2001-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -22,20 +22,13 @@ int
feholdexcept (fenv_t *envp)
{
unsigned int mxcsr;
- fenv_t temp;
- /* Store the environment. */
- __asm__ ("fnstenv %0\n"
- "stmxcsr %1" : "=m" (temp), "=m" (temp.__mxcsr));
- *envp = temp;
-
- /* Now set all exceptions to non-stop, first the x87 FPU. */
- temp.__control_word |= 0x3f;
-
- /* And clear all exceptions. */
- temp.__status_word &= ~0x3f;
-
- __asm__ ("fldenv %0" : : "m" (temp));
+ /* Store the environment. Recall that fnstenv has a side effect of
+ masking all exceptions. Then clear all exceptions. */
+ __asm__ ("fnstenv %0\n\t"
+ "stmxcsr %1\n\t"
+ "fnclex"
+ : "=m" (*envp), "=m" (envp->__mxcsr));
/* Set the SSE MXCSR register. */
mxcsr = (envp->__mxcsr | 0x1f80) & ~0x3f;
--
1.7.7.6