source: azure_iot_hub/trunk/musl-1.1.18/src/math/sincosf.c@ 389

Last change on this file since 389 was 389, checked in by coas-nagasima, 5 years ago

ビルドが通るよう更新
  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/x-csrc;charset=UTF-8
File size: 2.5 KB
Line 
1/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
2/*
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4 * Optimized by Bruce D. Evans.
5 */
6/*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
15 */
16
17#define _GNU_SOURCE
18#include "libm.h"
19
20/* Small multiples of pi/2 rounded to double precision. */
21static const double
22s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
23s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
24s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
25s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
26
27void sincosf(float x, float *sin, float *cos)
28{
29 double y;
30 float_t s, c;
31 uint32_t ix;
32 unsigned n, sign;
33
34 GET_FLOAT_WORD(ix, x);
35 sign = ix >> 31;
36 ix &= 0x7fffffff;
37
38 /* |x| ~<= pi/4 */
39 if (ix <= 0x3f490fda) {
40 /* |x| < 2**-12 */
41 if (ix < 0x39800000) {
42 /* raise inexact if x!=0 and underflow if subnormal */
43 FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f);
44 *sin = x;
45 *cos = 1.0f;
46 return;
47 }
48 *sin = __sindf(x);
49 *cos = __cosdf(x);
50 return;
51 }
52
53 /* |x| ~<= 5*pi/4 */
54 if (ix <= 0x407b53d1) {
55 if (ix <= 0x4016cbe3) { /* |x| ~<= 3pi/4 */
56 if (sign) {
57 *sin = -__cosdf(x + s1pio2);
58 *cos = __sindf(x + s1pio2);
59 } else {
60 *sin = __cosdf(s1pio2 - x);
61 *cos = __sindf(s1pio2 - x);
62 }
63 return;
64 }
65 /* -sin(x+c) is not correct if x+c could be 0: -0 vs +0 */
66 *sin = -__sindf(sign ? x + s2pio2 : x - s2pio2);
67 *cos = -__cosdf(sign ? x + s2pio2 : x - s2pio2);
68 return;
69 }
70
71 /* |x| ~<= 9*pi/4 */
72 if (ix <= 0x40e231d5) {
73 if (ix <= 0x40afeddf) { /* |x| ~<= 7*pi/4 */
74 if (sign) {
75 *sin = __cosdf(x + s3pio2);
76 *cos = -__sindf(x + s3pio2);
77 } else {
78 *sin = -__cosdf(x - s3pio2);
79 *cos = __sindf(x - s3pio2);
80 }
81 return;
82 }
83 *sin = __sindf(sign ? x + s4pio2 : x - s4pio2);
84 *cos = __cosdf(sign ? x + s4pio2 : x - s4pio2);
85 return;
86 }
87
88 /* sin(Inf or NaN) is NaN */
89 if (ix >= 0x7f800000) {
90 *sin = *cos = x - x;
91 return;
92 }
93
94 /* general argument reduction needed */
95 n = __rem_pio2f(x, &y);
96 s = __sindf(y);
97 c = __cosdf(y);
98 switch (n&3) {
99 case 0:
100 *sin = s;
101 *cos = c;
102 break;
103 case 1:
104 *sin = c;
105 *cos = -s;
106 break;
107 case 2:
108 *sin = -s;
109 *cos = -c;
110 break;
111 case 3:
112 default:
113 *sin = -c;
114 *cos = s;
115 break;
116 }
117}
Note: See TracBrowser for help on using the repository browser.