OpenCores
URL https://opencores.org/ocsvn/or1k/or1k/trunk

Subversion Repositories or1k

[/] [or1k/] [trunk/] [newlib-1.10.0/] [newlib/] [libm/] [math/] [s_sin.c] - Blame information for rev 1773

Go to most recent revision | Details | Compare with Previous | View Log

Line No. Rev Author Line
1 1010 ivang
 
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
/*
15
FUNCTION
16
        <<sin>>, <<sinf>>, <<cos>>, <<cosf>>---sine or cosine
17
INDEX
18
sin
19
INDEX
20
sinf
21
INDEX
22
cos
23
INDEX
24
cosf
25
ANSI_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
 
32
TRAD_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
 
44
DESCRIPTION
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
 
52
RETURNS
53
        The sine or cosine of <[x]> is returned.
54
 
55
PORTABILITY
56
        <<sin>> and <<cos>> are ANSI C.
57
        <<sinf>> and <<cosf>> are extensions.
58
 
59
QUICKREF
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 */

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.