1/* Test whether long double value is canonical. ldbl-96 version.
2 Copyright (C) 2016-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <float.h>
20#include <math.h>
21#include <math_private.h>
22#include <stdbool.h>
23#include <stdint.h>
24
25int
26__iscanonicall (long double x)
27{
28 uint32_t se, i0, i1 __attribute__ ((unused));
29
30 GET_LDOUBLE_WORDS (se, i0, i1, x);
31 int32_t ix = se & 0x7fff;
32 bool mant_high = (i0 & 0x80000000) != 0;
33
34 if (LDBL_MIN_EXP == -16381)
35 /* Intel variant: the high mantissa bit should have a value
36 determined by the exponent. */
37 return ix > 0 ? mant_high : !mant_high;
38 else
39 /* M68K variant: both values of the high bit are valid for the
40 greatest and smallest exponents, while other exponents require
41 the high bit to be set. */
42 return ix == 0 || ix == 0x7fff || mant_high;
43}
44libm_hidden_def (__iscanonicall)
45