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

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libquadmath/] [math/] [cosq.c] - Blame information for rev 740

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 740 jeremybenn 
/* s_cosl.c -- long double version of s_cos.c.
2 
 * Conversion to long double by Jakub Jelinek, jj@ultra.linux.cz.
3 
 */
4 
 
5 
/*
6 
 * ====================================================
7 
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 
 *
9 
 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 
 * Permission to use, copy, modify, and distribute this
11 
 * software is freely granted, provided that this notice
12 
 * is preserved.
13 
 * ====================================================
14 
 */
15 
 
16 
/* cosl(x)
17 
 * Return cosine function of x.
18 
 *
19 
 * kernel function:
20 
 *      __kernel_sinl           ... sine function on [-pi/4,pi/4]
21 
 *      __kernel_cosl           ... cosine function on [-pi/4,pi/4]
22 
 *      __ieee754_rem_pio2l     ... argument reduction routine
23 
 *
24 
 * Method.
25 
 *      Let S,C and T denote the sin, cos and tan respectively on
26 
 *      [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
27 
 *      in [-pi/4 , +pi/4], and let n = k mod 4.
28 
 *      We have
29 
 *
30 
 *          n        sin(x)      cos(x)        tan(x)
31 
 *     ----------------------------------------------------------
32 
 *          0          S           C             T
33 
 *          1          C          -S            -1/T
34 
 *          2         -S          -C             T
35 
 *          3         -C           S            -1/T
36 
 *     ----------------------------------------------------------
37 
 *
38 
 * Special cases:
39 
 *      Let trig be any of sin, cos, or tan.
40 
 *      trig(+-INF)  is NaN, with signals;
41 
 *      trig(NaN)    is that NaN;
42 
 *
43 
 * Accuracy:
44 
 *      TRIG(x) returns trig(x) nearly rounded
45 
 */
46 
 
47 
#include "quadmath-imp.h"
48 
 
49 
__float128
50 
cosq (__float128 x)
51 
{
52 
        __float128 y[2],z=0.0Q;
53 
        int64_t n, ix;
54 
 
55 
    /* High word of x. */
56 
        GET_FLT128_MSW64(ix,x);
57 
 
58 
    /* |x| ~< pi/4 */
59 
        ix &= 0x7fffffffffffffffLL;
60 
        if(ix <= 0x3ffe921fb54442d1LL)
61 
          return __quadmath_kernel_cosq(x,z);
62 
 
63 
    /* cos(Inf or NaN) is NaN */
64 
        else if (ix>=0x7fff000000000000LL) {
65 
            if (ix == 0x7fff000000000000LL) {
66 
                GET_FLT128_LSW64(n,x);
67 
            }
68 
            return x-x;
69 
        }
70 
 
71 
    /* argument reduction needed */
72 
        else {
73 
            n = __quadmath_rem_pio2q(x,y);
74 
            switch(n&3) {
75 
                case 0: return  __quadmath_kernel_cosq(y[0],y[1]);
76 
                case 1: return -__quadmath_kernel_sinq(y[0],y[1],1);
77 
                case 2: return -__quadmath_kernel_cosq(y[0],y[1]);
78 
                default:
79 
                        return  __quadmath_kernel_sinq(y[0],y[1],1);
80 
            }
81 
        }
82 
}

powered by: WebSVN 2.1.0

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