glibc/math/e_scalb_template.c

58 lines
1.6 KiB
C

/* Multiply by integral power of radix.
Copyright (C) 2011-2024 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
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
<https://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <libm-alias-finite.h>
static FLOAT
__attribute__ ((noinline))
invalid_fn (FLOAT x, FLOAT fn)
{
if (M_SUF (rint) (fn) != fn)
return (fn - fn) / (fn - fn);
else if (fn > M_LIT (65000.0))
return M_SUF (__scalbn) (x, 65000);
else
return M_SUF (__scalbn) (x,-65000);
}
FLOAT
M_DECL_FUNC (__ieee754_scalb) (FLOAT x, FLOAT fn)
{
if (__glibc_unlikely (isnan (x)))
return x * fn;
if (__glibc_unlikely (!isfinite (fn)))
{
if (isnan (fn) || fn > M_LIT (0.0))
return x * fn;
if (x == M_LIT (0.0))
return x;
return x / -fn;
}
if (__glibc_unlikely (M_FABS (fn) >= M_LIT (0x1p31)
|| (FLOAT) (int) fn != fn))
return invalid_fn (x, fn);
return M_SCALBN (x, (int) fn);
}
declare_mgen_finite_alias (__ieee754_scalb, __scalb)