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Diffstat (limited to 'libm/src/s_cos.c')
-rw-r--r-- | libm/src/s_cos.c | 82 |
1 files changed, 0 insertions, 82 deletions
diff --git a/libm/src/s_cos.c b/libm/src/s_cos.c deleted file mode 100644 index 0faf91e..0000000 --- a/libm/src/s_cos.c +++ /dev/null @@ -1,82 +0,0 @@ -/* @(#)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. - * ==================================================== - */ - -#ifndef lint -static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_cos.c,v 1.10 2005/10/24 14:08:36 bde 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" - -double -cos(double x) -{ - 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) { - if(ix<0x3e400000) /* if x < 2**-27 */ - if(((int)x)==0) return 1.0; /* generate inexact */ - 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); - } - } -} |