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      1 /* k_cosf.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 <sys/cdefs.h>
     17 #if defined(LIBM_SCCS) && !defined(lint)
     18 __RCSID("$NetBSD: k_cosf.c,v 1.7 2002/05/26 22:01:53 wiz Exp $");
     19 #endif
     20 
     21 #include "math.h"
     22 #include "math_private.h"
     23 
     24 static const float
     25 one =  1.0000000000e+00, /* 0x3f800000 */
     26 C1  =  4.1666667908e-02, /* 0x3d2aaaab */
     27 C2  = -1.3888889225e-03, /* 0xbab60b61 */
     28 C3  =  2.4801587642e-05, /* 0x37d00d01 */
     29 C4  = -2.7557314297e-07, /* 0xb493f27c */
     30 C5  =  2.0875723372e-09, /* 0x310f74f6 */
     31 C6  = -1.1359647598e-11; /* 0xad47d74e */
     32 
     33 float
     34 __kernel_cosf(float x, float y)
     35 {
     36 	float a,hz,z,r,qx;
     37 	int32_t ix;
     38 	GET_FLOAT_WORD(ix,x);
     39 	ix &= 0x7fffffff;			/* ix = |x|'s high word*/
     40 	if(ix<0x32000000) {			/* if x < 2**27 */
     41 	    if(((int)x)==0) return one;		/* generate inexact */
     42 	}
     43 	z  = x*x;
     44 	r  = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
     45 	if(ix < 0x3e99999a) 			/* if |x| < 0.3 */
     46 	    return one - ((float)0.5*z - (z*r - x*y));
     47 	else {
     48 	    if(ix > 0x3f480000) {		/* x > 0.78125 */
     49 		qx = (float)0.28125;
     50 	    } else {
     51 	        SET_FLOAT_WORD(qx,ix-0x01000000);	/* x/4 */
     52 	    }
     53 	    hz = (float)0.5*z-qx;
     54 	    a  = one-qx;
     55 	    return a - (hz - (z*r-x*y));
     56 	}
     57 }
     58