diff options
Diffstat (limited to 'libm/w_scalbf.c')
-rw-r--r-- | libm/w_scalbf.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/libm/w_scalbf.c b/libm/w_scalbf.c new file mode 100644 index 000000000..8e8a05b2e --- /dev/null +++ b/libm/w_scalbf.c @@ -0,0 +1,80 @@ +/* Copyright (C) 2011-2016 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, see + <http://www.gnu.org/licenses/>. */ + +#include <math.h> +#include "math_private.h" + +#if __UCLIBC_HAS_FENV__ +#include <errno.h> + +static float +__attribute__ ((noinline)) +sysv_scalbf (float x, float fn) +{ + float z = (float) __ieee754_scalb ((double) x, (double) fn); + + if (__builtin_expect (isinf (z),0)) + { + if (isfinite (x)) + return __kernel_standard_f (x, fn, 132); /* scalb overflow */ + else + __set_errno (ERANGE); + } + else if (__builtin_expect (z == 0.0f, 0) && z != x) + return __kernel_standard_f (x, fn, 133); /* scalb underflow */ + + return z; +} +#endif + +/* Wrapper scalbf */ +float +scalbf (float x, float fn) +{ +#if __UCLIBC_HAS_FENV__ + if (__builtin_expect (_LIB_VERSION == _SVID_, 0)) + return sysv_scalbf (x, fn); + else + { + float z = (float) __ieee754_scalb ((double) x, (double) fn); + + if (__builtin_expect (!isfinite (z) || z == 0.0f, 0)) + { + if (isnan (z)) + { + if (!isnan (x) && !isnan (fn)) + __set_errno (EDOM); + } + else if (isinf (z)) + { + if (!isinf (x) && !isinf (fn)) + __set_errno (ERANGE); + } + else + { + /* z == 0. */ + if (x != 0.0f && !isinf (fn)) + __set_errno (ERANGE); + } + } + return z; + } +#else + return (float) __ieee754_scalb ((double) x, (double) fn); +#endif /* __UCLIBC_HAS_FENV__ */ +} |