source: trunk/src/gcc/libjava/java/lang/s_sin.c@ 603

Last change on this file since 603 was 2, checked in by bird, 23 years ago

Initial revision
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  • Property svn:executable set to *
File size: 2.9 KB
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1
2/* @(#)s_sin.c 5.1 93/09/24 */
3/*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunPro, a Sun Microsystems, Inc. business.
8 * Permission to use, copy, modify, and distribute this
9 * software is freely granted, provided that this notice
10 * is preserved.
11 * ====================================================
12 */
13
14/*
15FUNCTION
16 <<sin>>, <<sinf>>, <<cos>>, <<cosf>>---sine or cosine
17INDEX
18sin
19INDEX
20sinf
21INDEX
22cos
23INDEX
24cosf
25ANSI_SYNOPSIS
26 #include <math.h>
27 double sin(double <[x]>);
28 float sinf(float <[x]>);
29 double cos(double <[x]>);
30 float cosf(float <[x]>);
31
32TRAD_SYNOPSIS
33 #include <math.h>
34 double sin(<[x]>)
35 double <[x]>;
36 float sinf(<[x]>)
37 float <[x]>;
38
39 double cos(<[x]>)
40 double <[x]>;
41 float cosf(<[x]>)
42 float <[x]>;
43
44DESCRIPTION
45 <<sin>> and <<cos>> compute (respectively) the sine and cosine
46 of the argument <[x]>. Angles are specified in radians.
47
48 <<sinf>> and <<cosf>> are identical, save that they take and
49 return <<float>> values.
50
51
52RETURNS
53 The sine or cosine of <[x]> is returned.
54
55PORTABILITY
56 <<sin>> and <<cos>> are ANSI C.
57 <<sinf>> and <<cosf>> are extensions.
58
59QUICKREF
60 sin ansi pure
61 sinf - pure
62*/
63
64/* sin(x)
65 * Return sine function of x.
66 *
67 * kernel function:
68 * __kernel_sin ... sine function on [-pi/4,pi/4]
69 * __kernel_cos ... cose function on [-pi/4,pi/4]
70 * __ieee754_rem_pio2 ... argument reduction routine
71 *
72 * Method.
73 * Let S,C and T denote the sin, cos and tan respectively on
74 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
75 * in [-pi/4 , +pi/4], and let n = k mod 4.
76 * We have
77 *
78 * n sin(x) cos(x) tan(x)
79 * ----------------------------------------------------------
80 * 0 S C T
81 * 1 C -S -1/T
82 * 2 -S -C T
83 * 3 -C S -1/T
84 * ----------------------------------------------------------
85 *
86 * Special cases:
87 * Let trig be any of sin, cos, or tan.
88 * trig(+-INF) is NaN, with signals;
89 * trig(NaN) is that NaN;
90 *
91 * Accuracy:
92 * TRIG(x) returns trig(x) nearly rounded
93 */
94
95#include "fdlibm.h"
96
97#ifndef _DOUBLE_IS_32BITS
98
99#ifdef __STDC__
100 double sin(double x)
101#else
102 double sin(x)
103 double x;
104#endif
105{
106 double y[2],z=0.0;
107 int32_t n,ix;
108
109 /* High word of x. */
110 GET_HIGH_WORD(ix,x);
111
112 /* |x| ~< pi/4 */
113 ix &= 0x7fffffff;
114 if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0);
115
116 /* sin(Inf or NaN) is NaN */
117 else if (ix>=0x7ff00000) return x-x;
118
119 /* argument reduction needed */
120 else {
121 n = __ieee754_rem_pio2(x,y);
122 switch(n&3) {
123 case 0: return __kernel_sin(y[0],y[1],1);
124 case 1: return __kernel_cos(y[0],y[1]);
125 case 2: return -__kernel_sin(y[0],y[1],1);
126 default:
127 return -__kernel_cos(y[0],y[1]);
128 }
129 }
130}
131
132#endif /* _DOUBLE_IS_32BITS */
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