1/* Compute remainder and a congruent to the quotient.
2 Copyright (C) 1997-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
5 Jakub Jelinek <jj@ultra.linux.cz>, 1999.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <https://www.gnu.org/licenses/>. */
20
21#include <math.h>
22
23#include <math_private.h>
24#include <libm-alias-ldouble.h>
25
26
27static const _Float128 zero = 0.0;
28
29
30_Float128
31__remquol (_Float128 x, _Float128 y, int *quo)
32{
33 int64_t hx,hy;
34 uint64_t sx,lx,ly,qs;
35 int cquo;
36
37 GET_LDOUBLE_WORDS64 (hx, lx, x);
38 GET_LDOUBLE_WORDS64 (hy, ly, y);
39 sx = hx & 0x8000000000000000ULL;
40 qs = sx ^ (hy & 0x8000000000000000ULL);
41 hy &= 0x7fffffffffffffffLL;
42 hx &= 0x7fffffffffffffffLL;
43
44 /* Purge off exception values. */
45 if ((hy | ly) == 0)
46 return (x * y) / (x * y); /* y = 0 */
47 if ((hx >= 0x7fff000000000000LL) /* x not finite */
48 || ((hy >= 0x7fff000000000000LL) /* y is NaN */
49 && (((hy - 0x7fff000000000000LL) | ly) != 0)))
50 return (x * y) / (x * y);
51
52 if (hy <= 0x7ffbffffffffffffLL)
53 x = __ieee754_fmodl (x, 8 * y); /* now x < 8y */
54
55 if (((hx - hy) | (lx - ly)) == 0)
56 {
57 *quo = qs ? -1 : 1;
58 return zero * x;
59 }
60
61 x = fabsl (x);
62 y = fabsl (y);
63 cquo = 0;
64
65 if (hy <= 0x7ffcffffffffffffLL && x >= 4 * y)
66 {
67 x -= 4 * y;
68 cquo += 4;
69 }
70 if (hy <= 0x7ffdffffffffffffLL && x >= 2 * y)
71 {
72 x -= 2 * y;
73 cquo += 2;
74 }
75
76 if (hy < 0x0002000000000000LL)
77 {
78 if (x + x > y)
79 {
80 x -= y;
81 ++cquo;
82 if (x + x >= y)
83 {
84 x -= y;
85 ++cquo;
86 }
87 }
88 }
89 else
90 {
91 _Float128 y_half = L(0.5) * y;
92 if (x > y_half)
93 {
94 x -= y;
95 ++cquo;
96 if (x >= y_half)
97 {
98 x -= y;
99 ++cquo;
100 }
101 }
102 }
103
104 *quo = qs ? -cquo : cquo;
105
106 /* Ensure correct sign of zero result in round-downward mode. */
107 if (x == 0)
108 x = 0;
109 if (sx)
110 x = -x;
111 return x;
112}
113libm_alias_ldouble (__remquo, remquo)
114