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      1 /* From: @(#)k_sin.c 1.3 95/01/18 */
      2 /*
      3  * ====================================================
      4  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
      5  * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans.
      6  *
      7  * Developed at SunSoft, a Sun Microsystems, Inc. business.
      8  * Permission to use, copy, modify, and distribute this
      9  * software is freely granted, provided that this notice
     10  * is preserved.
     11  * ====================================================
     12  */
     13 
     14 #include <sys/cdefs.h>
     15 /*
     16  * ld80 version of k_sin.c.  See ../src/k_sin.c for most comments.
     17  */
     18 
     19 #include "math_private.h"
     20 
     21 static const double
     22 half =  0.5;
     23 
     24 /*
     25  * Domain [-0.7854, 0.7854], range ~[-1.89e-22, 1.915e-22]
     26  * |sin(x)/x - s(x)| < 2**-72.1
     27  *
     28  * See ../ld80/k_cosl.c for more details about the polynomial.
     29  */
     30 #if defined(__amd64__) || defined(__i386__)
     31 /* Long double constants are slow on these arches, and broken on i386. */
     32 static const volatile double
     33 S1hi = -0.16666666666666666,		/* -0x15555555555555.0p-55 */
     34 S1lo = -9.2563760475949941e-18;		/* -0x15580000000000.0p-109 */
     35 #define	S1	((long double)S1hi + S1lo)
     36 #else
     37 static const long double
     38 S1 = -0.166666666666666666671L;		/* -0xaaaaaaaaaaaaaaab.0p-66 */
     39 #endif
     40 
     41 static const double
     42 S2 =  0.0083333333333333332,		/*  0x11111111111111.0p-59 */
     43 S3 = -0.00019841269841269427,		/* -0x1a01a01a019f81.0p-65 */
     44 S4 =  0.0000027557319223597490,		/*  0x171de3a55560f7.0p-71 */
     45 S5 = -0.000000025052108218074604,	/* -0x1ae64564f16cad.0p-78 */
     46 S6 =  1.6059006598854211e-10,		/*  0x161242b90243b5.0p-85 */
     47 S7 = -7.6429779983024564e-13,		/* -0x1ae42ebd1b2e00.0p-93 */
     48 S8 =  2.6174587166648325e-15;		/*  0x179372ea0b3f64.0p-101 */
     49 
     50 long double
     51 __kernel_sinl(long double x, long double y, int iy)
     52 {
     53 	long double z,r,v;
     54 
     55 	z	=  x*x;
     56 	v	=  z*x;
     57 	r	=  S2+z*(S3+z*(S4+z*(S5+z*(S6+z*(S7+z*S8)))));
     58 	if(iy==0) return x+v*(S1+z*r);
     59 	else      return x-((z*(half*y-v*r)-y)-v*S1);
     60 }
     61