glibc/math/w_scalb.c

57 lines
1.6 KiB
C

/* Copyright (C) 2011-2014 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 <errno.h>
#include <math.h>
#include <math_private.h>
static double
__attribute__ ((noinline))
sysv_scalb (double x, double fn)
{
double z = __ieee754_scalb (x, fn);
if (__glibc_unlikely (__isinf (z)))
{
if (__finite (x))
return __kernel_standard (x, fn, 32); /* scalb overflow */
else
__set_errno (ERANGE);
}
else if (__builtin_expect (z == 0.0, 0) && z != x)
return __kernel_standard (x, fn, 33); /* scalb underflow */
return z;
}
/* Wrapper scalb */
double
__scalb (double x, double fn)
{
return (__builtin_expect (_LIB_VERSION == _SVID_, 0)
? sysv_scalb (x, fn)
: __ieee754_scalb (x, fn));
}
weak_alias (__scalb, scalb)
#ifdef NO_LONG_DOUBLE
strong_alias (__scalb, __scalbl)
weak_alias (__scalb, scalbl)
#endif