s_cosf.c revision 152869
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 152869 2005-11-28 04:58:57Z bde $"; 18#endif 19 20#include "math.h" 21#define INLINE_KERNEL_COSDF 22#define INLINE_KERNEL_SINDF 23#include "math_private.h" 24#include "k_cosf.c" 25#include "k_sinf.c" 26 27/* Small multiples of pi/2 rounded to double precision. */ 28static const double 29c1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */ 30c2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */ 31c3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */ 32c4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ 33 34float 35cosf(float x) 36{ 37 float y[2]; 38 int32_t n,ix; 39 40 x = fabsf(x); 41 GET_FLOAT_WORD(ix,x); 42 43 if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ 44 if(ix<0x39800000) /* |x| < 2**-12 */ 45 if(((int)x)==0) return 1.0; /* 1 with inexact if x != 0 */ 46 return __kernel_cosdf(x); 47 } 48 if(ix<=0x407b53d1) { /* |x| <= ~5*pi/4 */ 49 if(ix<=0x4016cbe3) /* |x| <= ~3pi/4 */ 50 return -__kernel_sindf(x - c1pio2); 51 else 52 return -__kernel_cosdf(x - c2pio2); 53 } 54 if(ix<=0x40e231d5) { /* |x| <= ~9*pi/4 */ 55 if(ix<=0x40afeddf) /* |x| <= ~7*pi/4 */ 56 return __kernel_sindf(x - c3pio2); 57 else 58 return __kernel_cosdf(x - c4pio2); 59 } 60 61 /* cos(Inf or NaN) is NaN */ 62 else if (ix>=0x7f800000) return x-x; 63 64 /* general argument reduction needed */ 65 else { 66 n = __ieee754_rem_pio2f(x,y); 67 switch(n&3) { 68 case 0: return __kernel_cosdf((double)y[0]+y[1]); 69 case 1: return -__kernel_sindf((double)y[0]+y[1]); 70 case 2: return -__kernel_cosdf((double)y[0]+y[1]); 71 default: 72 return __kernel_sindf((double)y[0]+y[1]); 73 } 74 } 75} 76