s_cosf.c revision 151620
1/* s_cosf.c -- float version of s_cos.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 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#ifndef lint 17static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_cosf.c 151620 2005-10-24 14:08:36Z bde $"; 18#endif 19 20#include "math.h" 21#include "math_private.h" 22 23float 24cosf(float x) 25{ 26 float y[2],z=0.0; 27 int32_t n,ix; 28 29 GET_FLOAT_WORD(ix,x); 30 31 /* |x| ~< pi/4 */ 32 ix &= 0x7fffffff; 33 if(ix <= 0x3f490fd8) { 34 if(ix<0x39800000) /* if x < 2**-12 */ 35 if(((int)x)==0) return 1.0; /* generate inexact */ 36 return __kernel_cosf(x,z); 37 } 38 39 /* cos(Inf or NaN) is NaN */ 40 else if (ix>=0x7f800000) return x-x; 41 42 /* argument reduction needed */ 43 else { 44 n = __ieee754_rem_pio2f(x,y); 45 switch(n&3) { 46 case 0: return __kernel_cosf(y[0],y[1]); 47 case 1: return -__kernel_sinf(y[0],y[1],1); 48 case 2: return -__kernel_cosf(y[0],y[1]); 49 default: 50 return __kernel_sinf(y[0],y[1],1); 51 } 52 } 53} 54