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| author | Ulrich Drepper <drepper@gmail.com> | 2011-10-17 22:30:44 -0400 |
|---|---|---|
| committer | Ulrich Drepper <drepper@gmail.com> | 2011-10-17 22:30:44 -0400 |
| commit | 1004d1821ea9093f6b75e68047dc0b3d093578f7 (patch) | |
| tree | 53fb63ec39b87fbcfac1e0b119a6b8965a4e16cf | |
| parent | 228a984d543439308632ade9a77a171c88c11afc (diff) | |
| download | glibc-1004d1821ea9093f6b75e68047dc0b3d093578f7.tar.gz glibc-1004d1821ea9093f6b75e68047dc0b3d093578f7.tar.xz glibc-1004d1821ea9093f6b75e68047dc0b3d093578f7.zip | |
Add optimized 64-bit frexp
| -rw-r--r-- | ChangeLog | 2 | ||||
| -rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c | 67 |
2 files changed, 69 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index 081b4142ef..c47826c0f9 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,7 @@ 2011-10-17 Ulrich Drepper <drepper@gmail.com> + * sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c: New file. + * sysdeps/x86_64/fpu/math_private.h: Relax asm requirements for recently added interfaces. * sysdeps/x86_64/fpu/bits/mathinline.h: Likewise. diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c new file mode 100644 index 0000000000..76f7610804 --- /dev/null +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_frexp.c @@ -0,0 +1,67 @@ +/* Copyright (C) 2011 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@gmail.com>, 2011. + + 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <inttypes.h> +#include "math.h" +#include "math_private.h" + +/* + * for non-zero, finite x + * x = frexp(arg,&exp); + * return a double fp quantity x such that 0.5 <= |x| <1.0 + * and the corresponding binary exponent "exp". That is + * arg = x*2^exp. + * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg + * with *exp=0. + */ + + +double +__frexp (double x, int *eptr) +{ + int64_t ix; + EXTRACT_WORDS64 (ix, x); + int32_t ex = 0x7ff & (ix >> 52); + int e = 0; + + if (__builtin_expect (ex != 0x7ff && x != 0.0, 1)) + { + /* Not zero and finite. */ + e = ex - 1022; + if (__builtin_expect (ex == 0, 0)) + { + /* Subnormal. */ + x *= 0x1p54; + EXTRACT_WORDS64 (ix, x); + ex = 0x7ff & (ix >> 52); + e = ex - 1022 - 54; + } + + ix = (ix & INT64_C (0x800fffffffffffff)) | INT64_C (0x3fe0000000000000); + INSERT_WORDS64 (x, ix); + } + + *eptr = e; + return x; +} +weak_alias (__frexp, frexp) +#ifdef NO_LONG_DOUBLE +strong_alias (__frexp, __frexpl) +weak_alias (__frexp, frexpl) +#endif |