1/* Compute remainder and a congruent to the quotient.
2 Copyright (C) 1997-2022 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
21#include <math_private.h>
22
23
24static const float zero = 0.0;
25#include <libm-alias-float.h>
26
27
28float
29__remquof (float x, float y, int *quo)
30{
31 int32_t hx,hy;
32 uint32_t sx;
33 int cquo, qs;
34
35 GET_FLOAT_WORD (hx, x);
36 GET_FLOAT_WORD (hy, y);
37 sx = hx & 0x80000000;
38 qs = sx ^ (hy & 0x80000000);
39 hy &= 0x7fffffff;
40 hx &= 0x7fffffff;
41
42 /* Purge off exception values. */
43 if (hy == 0)
44 return (x * y) / (x * y); /* y = 0 */
45 if ((hx >= 0x7f800000) /* x not finite */
46 || (hy > 0x7f800000)) /* y is NaN */
47 return (x * y) / (x * y);
48
49 if (hy <= 0x7dffffff)
50 x = __ieee754_fmodf (x, 8 * y); /* now x < 8y */
51
52 if ((hx - hy) == 0)
53 {
54 *quo = qs ? -1 : 1;
55 return zero * x;
56 }
57
58 x = fabsf (x);
59 y = fabsf (y);
60 cquo = 0;
61
62 if (hy <= 0x7e7fffff && x >= 4 * y)
63 {
64 x -= 4 * y;
65 cquo += 4;
66 }
67 if (hy <= 0x7effffff && x >= 2 * y)
68 {
69 x -= 2 * y;
70 cquo += 2;
71 }
72
73 if (hy < 0x01000000)
74 {
75 if (x + x > y)
76 {
77 x -= y;
78 ++cquo;
79 if (x + x >= y)
80 {
81 x -= y;
82 ++cquo;
83 }
84 }
85 }
86 else
87 {
88 float y_half = 0.5 * y;
89 if (x > y_half)
90 {
91 x -= y;
92 ++cquo;
93 if (x >= y_half)
94 {
95 x -= y;
96 ++cquo;
97 }
98 }
99 }
100
101 *quo = qs ? -cquo : cquo;
102
103 /* Ensure correct sign of zero result in round-downward mode. */
104 if (x == 0.0f)
105 x = 0.0f;
106 if (sx)
107 x = -x;
108 return x;
109}
110libm_alias_float (__remquo, remquo)
111