s_cosf.c (1243B)
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 17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_cosf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 static const float one=1.0; 24 25 float 26 cosf(float x) 27 { 28 float y[2],z=0.0; 29 int32_t n,ix; 30 31 GET_FLOAT_WORD(ix,x); 32 33 /* |x| ~< pi/4 */ 34 ix &= 0x7fffffff; 35 if(ix <= 0x3f490fd8) return __kernel_cosf(x,z); 36 37 /* cos(Inf or NaN) is NaN */ 38 else if (ix>=0x7f800000) return x-x; 39 40 /* argument reduction needed */ 41 else { 42 n = __ieee754_rem_pio2f(x,y); 43 switch(n&3) { 44 case 0: return __kernel_cosf(y[0],y[1]); 45 case 1: return -__kernel_sinf(y[0],y[1],1); 46 case 2: return -__kernel_cosf(y[0],y[1]); 47 default: 48 return __kernel_sinf(y[0],y[1],1); 49 } 50 } 51 }