1/* Set NaN payload. 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 <math.h>
20#include <math_private.h>
21#include <libm-alias-ldouble.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 0x3fff
27#define PAYLOAD_DIG 62
28#define EXPLICIT_MANT_DIG 63
29
30int
31FUNC (long double *x, long double payload)
32{
33 uint32_t hx, lx;
34 uint16_t exponent;
35 GET_LDOUBLE_WORDS (exponent, hx, lx, payload);
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
40 && exponent == 0 && hx == 0 && lx == 0)))
41 {
42 SET_LDOUBLE_WORDS (*x, 0, 0, 0);
43 return 1;
44 }
45 int shift = BIAS + EXPLICIT_MANT_DIG - exponent;
46 if (shift < 32
47 ? (lx & ((1U << shift) - 1)) != 0
48 : (lx != 0 || (hx & ((1U << (shift - 32)) - 1)) != 0))
49 {
50 SET_LDOUBLE_WORDS (*x, 0, 0, 0);
51 return 1;
52 }
53 if (exponent != 0)
54 {
55 if (shift >= 32)
56 {
57 lx = hx >> (shift - 32);
58 hx = 0;
59 }
60 else if (shift != 0)
61 {
62 lx = (lx >> shift) | (hx << (32 - shift));
63 hx >>= shift;
64 }
65 }
66 hx |= 0x80000000 | (SET_HIGH_BIT ? 0x40000000 : 0);
67 SET_LDOUBLE_WORDS (*x, 0x7fff, hx, lx);
68 return 0;
69}
70