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| author | Richard Henderson <rth@twiddle.net> | 2012-03-18 15:51:53 -0700 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2012-03-19 06:51:06 -0700 |
| commit | d0adc9223031b606c3c7781b4ec41462796ab313 (patch) | |
| tree | dabdb4d73fadc785c77dfb54db347c777c5a1304 | |
| parent | 0fe0f1f86f82f9e08ca4d4b85111de03f4c2f876 (diff) | |
| download | glibc-d0adc9223031b606c3c7781b4ec41462796ab313.tar.gz glibc-d0adc9223031b606c3c7781b4ec41462796ab313.tar.xz glibc-d0adc9223031b606c3c7781b4ec41462796ab313.zip | |
i386/x86_64: Optimize feholdexcept.
| -rw-r--r-- | ChangeLog | 3 | ||||
| -rw-r--r-- | sysdeps/i386/fpu/feholdexcpt.c | 19 | ||||
| -rw-r--r-- | sysdeps/x86_64/fpu/feholdexcpt.c | 21 |
3 files changed, 14 insertions, 29 deletions
diff --git a/ChangeLog b/ChangeLog index 12a99d2bf7..7efa13b5bd 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,8 @@ 2012-03-19 Richard Henderson <rth@twiddle.net> + * sysdeps/i386/fpu/feholdexcpt.c (feholdexcept): Avoid the fldenv. + * sysdeps/x86_64/fpu/feholdexcpt.c (feholdexcept): Likewise. + * sysdeps/generic/math_private.h (default_libc_feupdateenv_test): New. (libc_feupdateenv_test, libc_feupdateenv_testf): New. (libc_feupdateenv_testl): New. diff --git a/sysdeps/i386/fpu/feholdexcpt.c b/sysdeps/i386/fpu/feholdexcpt.c index a09d45ebd0..7e1038955f 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. @@ -26,19 +25,9 @@ int 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 b547b34957..b380479153 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; |