1 /* kf_cos.c -- float version of k_cos.c 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) 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 #include "fdlibm.h" 17 18 #ifdef __STDC__ 19 static const float 20 #else 21 static float 22 #endif 23 one = 1.0000000000e+00, /* 0x3f800000 */ 24 C1 = 4.1666667908e-02, /* 0x3d2aaaab */ 25 C2 = -1.3888889225e-03, /* 0xbab60b61 */ 26 C3 = 2.4801587642e-05, /* 0x37d00d01 */ 27 C4 = -2.7557314297e-07, /* 0xb493f27c */ 28 C5 = 2.0875723372e-09, /* 0x310f74f6 */ 29 C6 = -1.1359647598e-11; /* 0xad47d74e */ 30 31 #ifdef __STDC__ 32 float __kernel_cosf(float x, float y) 33 #else 34 float __kernel_cosf(x, y) 35 float x,y; 36 #endif 37 { 38 float a,hz,z,r,qx; 39 __int32_t ix; 40 GET_FLOAT_WORD(ix,x); 41 ix &= 0x7fffffff; /* ix = |x|'s high word*/ 42 if(ix<0x32000000) { /* if x < 2**27 */ 43 if(((int)x)==0) return one; /* generate inexact */ 44 } 45 z = x*x; 46 r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6))))); 47 if(ix < 0x3e99999a) /* if |x| < 0.3 */ 48 return one - ((float)0.5*z - (z*r - x*y)); 49 else { 50 if(ix > 0x3f480000) { /* x > 0.78125 */ 51 qx = (float)0.28125; 52 } else { 53 SET_FLOAT_WORD(qx,ix-0x01000000); /* x/4 */ 54 } 55 hz = (float)0.5*z-qx; 56 a = one-qx; 57 return a - (hz - (z*r-x*y)); 58 } 59 } 60
