1 /* Compute sine of argument.
2 Copyright (C) 2018-2021 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 <stdint.h>
20 #include <math.h>
21 #include <math-barriers.h>
22 #include <libm-alias-float.h>
23 #include "math_config.h"
24 #include "s_sincosf.h"
25
26 #ifndef SINF
27 # define SINF_FUNC __sinf
28 #else
29 # define SINF_FUNC SINF
30 #endif
31
32 /* Fast sinf implementation. Worst-case ULP is 0.5607, maximum relative
33 error is 0.5303 * 2^-23. A single-step range reduction is used for
34 small values. Large inputs have their range reduced using fast integer
35 arithmetic.
36 */
37 float
SINF_FUNC(float y)38 SINF_FUNC (float y)
39 {
40 double x = y;
41 double s;
42 int n;
43 const sincos_t *p = &__sincosf_table[0];
44
45 if (abstop12 (y) < abstop12 (pio4))
46 {
47 s = x * x;
48
49 if (__glibc_unlikely (abstop12 (y) < abstop12 (0x1p-12f)))
50 {
51 /* Force underflow for tiny y. */
52 if (__glibc_unlikely (abstop12 (y) < abstop12 (0x1p-126f)))
53 math_force_eval ((float)s);
54 return y;
55 }
56
57 return sinf_poly (x, s, p, 0);
58 }
59 else if (__glibc_likely (abstop12 (y) < abstop12 (120.0f)))
60 {
61 x = reduce_fast (x, p, &n);
62
63 /* Setup the signs for sin and cos. */
64 s = p->sign[n & 3];
65
66 if (n & 2)
67 p = &__sincosf_table[1];
68
69 return sinf_poly (x * s, x * x, p, n);
70 }
71 else if (abstop12 (y) < abstop12 (INFINITY))
72 {
73 uint32_t xi = asuint (y);
74 int sign = xi >> 31;
75
76 x = reduce_large (xi, &n);
77
78 /* Setup signs for sin and cos - include original sign. */
79 s = p->sign[(n + sign) & 3];
80
81 if ((n + sign) & 2)
82 p = &__sincosf_table[1];
83
84 return sinf_poly (x * s, x * x, p, n);
85 }
86 else
87 return __math_invalidf (y);
88 }
89
90 #ifndef SINF
91 libm_alias_float (__sin, sin)
92 #endif
93