xref: /freebsd/lib/msun/src/k_cosf.c (revision f4b01a9edf59b9d3091f4fa787a899090a4414b4)
13a8617a8SJordan K. Hubbard /* k_cosf.c -- float version of k_cos.c
23a8617a8SJordan K. Hubbard  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
311dc2417SBruce Evans  * Debugged and optimized by Bruce D. Evans.
43a8617a8SJordan K. Hubbard  */
53a8617a8SJordan K. Hubbard 
63a8617a8SJordan K. Hubbard /*
73a8617a8SJordan K. Hubbard  * ====================================================
83a8617a8SJordan K. Hubbard  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
93a8617a8SJordan K. Hubbard  *
103a8617a8SJordan K. Hubbard  * Developed at SunPro, a Sun Microsystems, Inc. business.
113a8617a8SJordan K. Hubbard  * Permission to use, copy, modify, and distribute this
123a8617a8SJordan K. Hubbard  * software is freely granted, provided that this notice
133a8617a8SJordan K. Hubbard  * is preserved.
143a8617a8SJordan K. Hubbard  * ====================================================
153a8617a8SJordan K. Hubbard  */
163a8617a8SJordan K. Hubbard 
1759aad933SBruce Evans #ifndef INLINE_KERNEL_COSDF
183a8617a8SJordan K. Hubbard #ifndef lint
197f3dea24SPeter Wemm static char rcsid[] = "$FreeBSD$";
203a8617a8SJordan K. Hubbard #endif
214ce51209SBruce Evans #endif
223a8617a8SJordan K. Hubbard 
233a8617a8SJordan K. Hubbard #include "math.h"
243a8617a8SJordan K. Hubbard #include "math_private.h"
253a8617a8SJordan K. Hubbard 
2659aad933SBruce Evans /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
2759aad933SBruce Evans static const double
2811dc2417SBruce Evans one =  1.0,
2959aad933SBruce Evans C0  = -0x1ffffffd0c5e81.0p-54,	/* -0.499999997251031003120 */
3059aad933SBruce Evans C1  =  0x155553e1053a42.0p-57,	/*  0.0416666233237390631894 */
3159aad933SBruce Evans C2  = -0x16c087e80f1e27.0p-62,	/* -0.00138867637746099294692 */
3259aad933SBruce Evans C3  =  0x199342e0ee5069.0p-68;	/*  0.0000243904487962774090654 */
333a8617a8SJordan K. Hubbard 
3459aad933SBruce Evans #ifdef INLINE_KERNEL_COSDF
354ce51209SBruce Evans extern inline
364ce51209SBruce Evans #endif
3759b19ff1SAlfred Perlstein float
3859aad933SBruce Evans __kernel_cosdf(double x)
393a8617a8SJordan K. Hubbard {
40f4b01a9eSBruce Evans 	double r, w, z;
413b46e988SBruce Evans 
42f4b01a9eSBruce Evans 	/* Try to optimize for parallel evaluation as in k_tanf.c. */
433a8617a8SJordan K. Hubbard 	z = x*x;
44f4b01a9eSBruce Evans 	w = z*z;
45f4b01a9eSBruce Evans 	r = C2+z*C3;
46f4b01a9eSBruce Evans 	return ((one+z*C0) + w*C1) + (w*z)*r;
473a8617a8SJordan K. Hubbard }
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