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