glibc/sysdeps/ieee754/ldbl-96/s_iscanonicall.c

45 lines
1.6 KiB
C

/* Test whether long double value is canonical. ldbl-96 version.
Copyright (C) 2016-2023 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 <float.h>
#include <math.h>
#include <math_private.h>
#include <stdbool.h>
#include <stdint.h>
int
__iscanonicall (long double x)
{
uint32_t se, i0, i1 __attribute__ ((unused));
GET_LDOUBLE_WORDS (se, i0, i1, x);
int32_t ix = se & 0x7fff;
bool mant_high = (i0 & 0x80000000) != 0;
if (LDBL_MIN_EXP == -16381)
/* Intel variant: the high mantissa bit should have a value
determined by the exponent. */
return ix > 0 ? mant_high : !mant_high;
else
/* M68K variant: both values of the high bit are valid for the
greatest and smallest exponents, while other exponents require
the high bit to be set. */
return ix == 0 || ix == 0x7fff || mant_high;
}
libm_hidden_def (__iscanonicall)