1/* Round to integer type. ldbl-128 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 <errno.h>
20#include <fenv.h>
21#include <math.h>
22#include <math_private.h>
23#include <libm-alias-ldouble.h>
24#include <stdbool.h>
25#include <stdint.h>
26
27#define BIAS 0x3fff
28#define MANT_DIG 113
29
30#if UNSIGNED
31# define RET_TYPE uintmax_t
32#else
33# define RET_TYPE intmax_t
34#endif
35
36#include <fromfp.h>
37
38RET_TYPE
39FUNC (_Float128 x, int round, unsigned int width)
40{
41 if (width > INTMAX_WIDTH)
42 width = INTMAX_WIDTH;
43 uint64_t hx, lx;
44 GET_LDOUBLE_WORDS64 (hx, lx, x);
45 bool negative = (hx & 0x8000000000000000ULL) != 0;
46 if (width == 0)
47 return fromfp_domain_error (negative, width);
48 hx &= 0x7fffffffffffffffULL;
49 if ((hx | lx) == 0)
50 return 0;
51 int exponent = hx >> (MANT_DIG - 1 - 64);
52 exponent -= BIAS;
53 int max_exponent = fromfp_max_exponent (negative, width);
54 if (exponent > max_exponent)
55 return fromfp_domain_error (negative, width);
56
57 hx &= ((1ULL << (MANT_DIG - 1 - 64)) - 1);
58 hx |= 1ULL << (MANT_DIG - 1 - 64);
59 uintmax_t uret;
60 bool half_bit, more_bits;
61 /* The exponent is at most 63, so we are shifting right by at least
62 49 bits. */
63 if (exponent >= -1)
64 {
65 int shift = MANT_DIG - 1 - exponent;
66 if (shift <= 64)
67 {
68 uint64_t h = 1ULL << (shift - 1);
69 half_bit = (lx & h) != 0;
70 more_bits = (lx & (h - 1)) != 0;
71 uret = hx << (64 - shift);
72 if (shift != 64)
73 uret |= lx >> shift;
74 }
75 else
76 {
77 uint64_t h = 1ULL << (shift - 1 - 64);
78 half_bit = (hx & h) != 0;
79 more_bits = ((hx & (h - 1)) | lx) != 0;
80 uret = hx >> (shift - 64);
81 }
82 }
83 else
84 {
85 uret = 0;
86 half_bit = false;
87 more_bits = true;
88 }
89 return fromfp_round_and_return (negative, uret, half_bit, more_bits, round,
90 exponent, max_exponent, width);
91}
92