1 /* Set NaN payload. flt-32 version.
2 Copyright (C) 2016-2021 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 <math.h>
20 #include <math_private.h>
21 #include <libm-alias-float.h>
22 #include <nan-high-order-bit.h>
23 #include <stdint.h>
24
25 #define SET_HIGH_BIT (HIGH_ORDER_BIT_IS_SET_FOR_SNAN ? SIG : !SIG)
26 #define BIAS 0x7f
27 #define PAYLOAD_DIG 22
28 #define EXPLICIT_MANT_DIG 23
29
30 int
FUNC(float * x,float payload)31 FUNC (float *x, float payload)
32 {
33 uint32_t ix;
34 GET_FLOAT_WORD (ix, payload);
35 int exponent = ix >> EXPLICIT_MANT_DIG;
36 /* Test if argument is (a) negative or too large; (b) too small,
37 except for 0 when allowed; (c) not an integer. */
38 if (exponent >= BIAS + PAYLOAD_DIG
39 || (exponent < BIAS && !(SET_HIGH_BIT && ix == 0))
40 || (ix & ((1U << (BIAS + EXPLICIT_MANT_DIG - exponent)) - 1)) != 0)
41 {
42 SET_FLOAT_WORD (*x, 0);
43 return 1;
44 }
45 if (ix != 0)
46 {
47 ix &= (1U << EXPLICIT_MANT_DIG) - 1;
48 ix |= 1U << EXPLICIT_MANT_DIG;
49 ix >>= BIAS + EXPLICIT_MANT_DIG - exponent;
50 }
51 ix |= 0x7f800000 | (SET_HIGH_BIT ? 0x400000 : 0);
52 SET_FLOAT_WORD (*x, ix);
53 return 0;
54 }
55