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 "cdefs-compat.h" 18 //__FBSDID("$FreeBSD: src/lib/msun/src/s_cosf.c,v 1.18 2008/02/25 22:19:17 bde Exp $"); 19 20 #include <float.h> 21 22 #include "openlibm.h" 23 //#define INLINE_KERNEL_COSDF 24 //#define INLINE_KERNEL_SINDF 25 //#define INLINE_REM_PIO2F 26 #include "math_private.h" 27 //#include "e_rem_pio2f.c" 28 //#include "k_cosf.c" 29 //#include "k_sinf.c" 30 31 /* Small multiples of pi/2 rounded to double precision. */ 32 static const double 33 c1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */ 34 c2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */ 35 c3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */ 36 c4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ 37 38 float 39 cosf(float x) 40 { 41 double y; 42 int32_t n, hx, ix; 43 44 GET_FLOAT_WORD(hx,x); 45 ix = hx & 0x7fffffff; 46 47 if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ 48 if(ix<0x39800000) /* |x| < 2**-12 */ 49 if(((int)x)==0) return 1.0; /* 1 with inexact if x != 0 */ 50 return __kernel_cosdf(x); 51 } 52 if(ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */ 53 if(ix>0x4016cbe3) /* |x| ~> 3*pi/4 */ 54 return -__kernel_cosdf(x + (hx > 0 ? -c2pio2 : c2pio2)); 55 else { 56 if(hx>0) 57 return __kernel_sindf(c1pio2 - x); 58 else 59 return __kernel_sindf(x + c1pio2); 60 } 61 } 62 if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */ 63 if(ix>0x40afeddf) /* |x| ~> 7*pi/4 */ 64 return __kernel_cosdf(x + (hx > 0 ? -c4pio2 : c4pio2)); 65 else { 66 if(hx>0) 67 return __kernel_sindf(x - c3pio2); 68 else 69 return __kernel_sindf(-c3pio2 - x); 70 } 71 } 72 73 /* cos(Inf or NaN) is NaN */ 74 else if (ix>=0x7f800000) return x-x; 75 76 /* general argument reduction needed */ 77 else { 78 n = __ieee754_rem_pio2f(x,&y); 79 switch(n&3) { 80 case 0: return __kernel_cosdf(y); 81 case 1: return __kernel_sindf(-y); 82 case 2: return -__kernel_cosdf(y); 83 default: 84 return __kernel_sindf(y); 85 } 86 } 87 } 88