s_cosf.c revision 176552
1/* s_cosf.c -- float version of s_cos.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 * Optimized by Bruce D. Evans. 4 */ 5 6/* 7 * ==================================================== 8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 9 * 10 * Developed at SunPro, a Sun Microsystems, Inc. business. 11 * Permission to use, copy, modify, and distribute this 12 * software is freely granted, provided that this notice 13 * is preserved. 14 * ==================================================== 15 */ 16 17#include <sys/cdefs.h> 18__FBSDID("$FreeBSD: head/lib/msun/src/s_cosf.c 176552 2008-02-25 13:33:20Z bde $"); 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 double y; 38 int32_t n, hx, ix; 39 40 GET_FLOAT_WORD(hx,x); 41 ix = hx & 0x7fffffff; 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| ~> 3*pi/4 */ 50 return -__kernel_cosdf(x + (hx > 0 ? -c2pio2 : c2pio2)); 51 else { 52 if(hx>0) 53 return __kernel_sindf(c1pio2 - x); 54 else 55 return __kernel_sindf(x + c1pio2); 56 } 57 } 58 if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */ 59 if(ix>0x40afeddf) /* |x| ~> 7*pi/4 */ 60 return __kernel_cosdf(x + (hx > 0 ? -c4pio2 : c4pio2)); 61 else { 62 if(hx>0) 63 return __kernel_sindf(x - c3pio2); 64 else 65 return __kernel_sindf(-c3pio2 - x); 66 } 67 } 68 69 /* cos(Inf or NaN) is NaN */ 70 else if (ix>=0x7f800000) return x-x; 71 72 /* general argument reduction needed */ 73 else { 74 n = __ieee754_rem_pio2f(x,&y); 75 switch(n&3) { 76 case 0: return __kernel_cosdf(y); 77 case 1: return __kernel_sindf(-y); 78 case 2: return -__kernel_cosdf(y); 79 default: 80 return __kernel_sindf(y); 81 } 82 } 83} 84