48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
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/* k_cosf.c -- float version of k_cos.c
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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* Debugged and optimized by Bruce D. Evans.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#ifndef INLINE_KERNEL_COSDF
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#ifndef lint
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static char rcsid[] = "$FreeBSD: src/lib/msun/src/k_cosf.c,v 1.15 2005/11/30 11:51:17 bde Exp $";
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#endif
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#endif
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#include "math.h"
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#include "math_private.h"
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/* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
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static const double
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one = 1.0,
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C0 = -0x1ffffffd0c5e81.0p-54, /* -0.499999997251031003120 */
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C1 = 0x155553e1053a42.0p-57, /* 0.0416666233237390631894 */
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C2 = -0x16c087e80f1e27.0p-62, /* -0.00138867637746099294692 */
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C3 = 0x199342e0ee5069.0p-68; /* 0.0000243904487962774090654 */
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#ifdef INLINE_KERNEL_COSDF
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extern inline
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#endif
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float
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__kernel_cosdf(double x)
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{
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double r, w, z;
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/* Try to optimize for parallel evaluation as in k_tanf.c. */
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z = x*x;
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w = z*z;
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r = C2+z*C3;
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return ((one+z*C0) + w*C1) + (w*z)*r;
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}
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