1 /* origin: FreeBSD /usr/src/lib/msun/src/s_cosf.c */
3 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4 * Optimized by Bruce D. Evans.
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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
14 * ====================================================
19 /* Small multiples of pi/2 rounded to double precision. */
21 c1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
22 c2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
23 c3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
24 c4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
31 GET_FLOAT_WORD(hx, x);
33 if (ix <= 0x3f490fda) { /* |x| ~<= pi/4 */
34 if (ix < 0x39800000) /* |x| < 2**-12 */
35 if ((int)x == 0) /* raise inexact if x != 0 */
39 if (ix <= 0x407b53d1) { /* |x| ~<= 5*pi/4 */
40 if (ix > 0x4016cbe3) /* |x| ~> 3*pi/4 */
41 return -__cosdf(hx > 0 ? x-c2pio2 : x+c2pio2);
44 return __sindf(c1pio2 - x);
46 return __sindf(x + c1pio2);
49 if (ix <= 0x40e231d5) { /* |x| ~<= 9*pi/4 */
50 if (ix > 0x40afeddf) /* |x| ~> 7*pi/4 */
51 return __cosdf(hx > 0 ? x-c4pio2 : x+c4pio2);
54 return __sindf(x - c3pio2);
56 return __sindf(-c3pio2 - x);
60 /* cos(Inf or NaN) is NaN */
64 /* general argument reduction needed */
65 n = __rem_pio2f(x,&y);
67 case 0: return __cosdf(y);
68 case 1: return __sindf(-y);
69 case 2: return -__cosdf(y);