diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_cos.c')
-rw-r--r-- | sysdeps/ieee754/dbl-64/s_cos.c | 88 |
1 files changed, 1 insertions, 87 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_cos.c b/sysdeps/ieee754/dbl-64/s_cos.c index 7edb5deafe..4be1276ccb 100644 --- a/sysdeps/ieee754/dbl-64/s_cos.c +++ b/sysdeps/ieee754/dbl-64/s_cos.c @@ -1,87 +1 @@ -/* @(#)s_cos.c 5.1 93/09/24 */ -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunPro, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ - -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: s_cos.c,v 1.7 1995/05/10 20:47:02 jtc Exp $"; -#endif - -/* cos(x) - * Return cosine function of x. - * - * kernel function: - * __kernel_sin ... sine function on [-pi/4,pi/4] - * __kernel_cos ... cosine function on [-pi/4,pi/4] - * __ieee754_rem_pio2 ... argument reduction routine - * - * Method. - * Let S,C and T denote the sin, cos and tan respectively on - * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2 - * in [-pi/4 , +pi/4], and let n = k mod 4. - * We have - * - * n sin(x) cos(x) tan(x) - * ---------------------------------------------------------- - * 0 S C T - * 1 C -S -1/T - * 2 -S -C T - * 3 -C S -1/T - * ---------------------------------------------------------- - * - * Special cases: - * Let trig be any of sin, cos, or tan. - * trig(+-INF) is NaN, with signals; - * trig(NaN) is that NaN; - * - * Accuracy: - * TRIG(x) returns trig(x) nearly rounded - */ - -#include "math.h" -#include "math_private.h" - -#ifdef __STDC__ - double __cos(double x) -#else - double __cos(x) - double x; -#endif -{ - double y[2],z=0.0; - int32_t n, ix; - - /* High word of x. */ - GET_HIGH_WORD(ix,x); - - /* |x| ~< pi/4 */ - ix &= 0x7fffffff; - if(ix <= 0x3fe921fb) return __kernel_cos(x,z); - - /* cos(Inf or NaN) is NaN */ - else if (ix>=0x7ff00000) return x-x; - - /* argument reduction needed */ - else { - n = __ieee754_rem_pio2(x,y); - switch(n&3) { - case 0: return __kernel_cos(y[0],y[1]); - case 1: return -__kernel_sin(y[0],y[1],1); - case 2: return -__kernel_cos(y[0],y[1]); - default: - return __kernel_sin(y[0],y[1],1); - } - } -} -weak_alias (__cos, cos) -#ifdef NO_LONG_DOUBLE -strong_alias (__cos, __cosl) -weak_alias (__cos, cosl) -#endif +/* In s_sin.c. */ |