From ef72d5f1b95fe91b032de0ad1ee777d7cf4fb49f Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Mon, 24 Aug 2009 10:20:58 -0700 Subject: [PATCH] Optimize x86-64 signbit{,f} a bit. --- ChangeLog | 5 +++++ sysdeps/x86_64/fpu/bits/mathinline.h | 12 +++++++----- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/ChangeLog b/ChangeLog index 9f63c4db05..45ff958cb8 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2009-08-24 Ulrich Drepper + + * sysdeps/x86_64/fpu/bits/mathinline.h (__signbit): Optimize. + (__signbitf): Likewise. + 2009-08-23 Ulrich Drepper * posix/regcomp.c (parse_dup_op): Verify the expression is correctly diff --git a/sysdeps/x86_64/fpu/bits/mathinline.h b/sysdeps/x86_64/fpu/bits/mathinline.h index e8a919fe92..8d4850dfc0 100644 --- a/sysdeps/x86_64/fpu/bits/mathinline.h +++ b/sysdeps/x86_64/fpu/bits/mathinline.h @@ -1,5 +1,5 @@ /* Inline math functions for x86-64. - Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc. + Copyright (C) 2002, 2003, 2004, 2007, 2009 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Andreas Jaeger , 2002. @@ -35,14 +35,16 @@ __MATH_INLINE int __NTH (__signbitf (float __x)) { - __extension__ union { float __f; int __i; } __u = { __f: __x }; - return __u.__i < 0; + int __m; + asm ("pmovmskb %1, %0" : "=r" (__m) : "x" (__x)); + return __m & 0x8; } __MATH_INLINE int __NTH (__signbit (double __x)) { - __extension__ union { double __d; int __i[2]; } __u = { __d: __x }; - return __u.__i[1] < 0; + int __m; + asm ("pmovmskb %1, %0" : "=r" (__m) : "x" (__x)); + return __m & 0x80; } __MATH_INLINE int __NTH (__signbitl (long double __x))