math: fix pow signed shift ub
[oweals/musl.git] / src / math / sincosf.c
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. */
21 static const double
22 s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
23 s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
24 s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
25 s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
26
27 void 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 }