fixes for host gcc 4.6.1
[zpugcc/jano.git] / toolchain / gcc / libjava / java / lang / s_cos.c
blobbe1538d4c0b639818345884bb0c423e8b6222c2c
2 /* @(#)s_cos.c 5.1 93/09/24 */
3 /*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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 * ====================================================
14 /* cos(x)
15 * Return cosine function of x.
17 * kernel function:
18 * __kernel_sin ... sine function on [-pi/4,pi/4]
19 * __kernel_cos ... cosine function on [-pi/4,pi/4]
20 * __ieee754_rem_pio2 ... argument reduction routine
22 * Method.
23 * Let S,C and T denote the sin, cos and tan respectively on
24 * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
25 * in [-pi/4 , +pi/4], and let n = k mod 4.
26 * We have
28 * n sin(x) cos(x) tan(x)
29 * ----------------------------------------------------------
30 * 0 S C T
31 * 1 C -S -1/T
32 * 2 -S -C T
33 * 3 -C S -1/T
34 * ----------------------------------------------------------
36 * Special cases:
37 * Let trig be any of sin, cos, or tan.
38 * trig(+-INF) is NaN, with signals;
39 * trig(NaN) is that NaN;
41 * Accuracy:
42 * TRIG(x) returns trig(x) nearly rounded
45 #include "fdlibm.h"
47 #ifndef _DOUBLE_IS_32BITS
49 #ifdef __STDC__
50 double cos(double x)
51 #else
52 double cos(x)
53 double x;
54 #endif
56 double y[2],z=0.0;
57 int32_t n,ix;
59 /* High word of x. */
60 GET_HIGH_WORD(ix,x);
62 /* |x| ~< pi/4 */
63 ix &= 0x7fffffff;
64 if(ix <= 0x3fe921fb) return __kernel_cos(x,z);
66 /* cos(Inf or NaN) is NaN */
67 else if (ix>=0x7ff00000) return x-x;
69 /* argument reduction needed */
70 else {
71 n = __ieee754_rem_pio2(x,y);
72 switch(n&3) {
73 case 0: return __kernel_cos(y[0],y[1]);
74 case 1: return -__kernel_sin(y[0],y[1],1);
75 case 2: return -__kernel_cos(y[0],y[1]);
76 default:
77 return __kernel_sin(y[0],y[1],1);
82 #endif /* _DOUBLE_IS_32BITS */