1/* Set NaN payload. ldbl-96 version.
2 Copyright (C) 2016-2017 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 <http://www.gnu.org/licenses/>. */
18
19#include <math.h>
20#include <math_private.h>
21#include <nan-high-order-bit.h>
22#include <stdint.h>
23
24#define SET_HIGH_BIT (HIGH_ORDER_BIT_IS_SET_FOR_SNAN ? SIG : !SIG)
25#define BIAS 0x3fff
26#define PAYLOAD_DIG 62
27#define EXPLICIT_MANT_DIG 63
28
29int
30FUNC (long double *x, long double payload)
31{
32 uint32_t hx, lx;
33 uint16_t exponent;
34 GET_LDOUBLE_WORDS (exponent, hx, lx, payload);
35 /* Test if argument is (a) negative or too large; (b) too small,
36 except for 0 when allowed; (c) not an integer. */
37 if (exponent >= BIAS + PAYLOAD_DIG
38 || (exponent < BIAS && !(SET_HIGH_BIT
39 && exponent == 0 && hx == 0 && lx == 0)))
40 {
41 SET_LDOUBLE_WORDS (*x, 0, 0, 0);
42 return 1;
43 }
44 int shift = BIAS + EXPLICIT_MANT_DIG - exponent;
45 if (shift < 32
46 ? (lx & ((1U << shift) - 1)) != 0
47 : (lx != 0 || (hx & ((1U << (shift - 32)) - 1)) != 0))
48 {
49 SET_LDOUBLE_WORDS (*x, 0, 0, 0);
50 return 1;
51 }
52 if (exponent != 0)
53 {
54 if (shift >= 32)
55 {
56 lx = hx >> (shift - 32);
57 hx = 0;
58 }
59 else if (shift != 0)
60 {
61 lx = (lx >> shift) | (hx << (32 - shift));
62 hx >>= shift;
63 }
64 }
65 hx |= 0x80000000 | (SET_HIGH_BIT ? 0x40000000 : 0);
66 SET_LDOUBLE_WORDS (*x, 0x7fff, hx, lx);
67 return 0;
68}
69