compiler/stdc/math/k_cosf.c

   1 /* k_cosf.c -- float version of k_cos.c
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  * Debugged and optimized by Bruce D. Evans.
   4  */
   5
   6 /*
   7  * ====================================================
   8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   9  *
  10  * Developed at SunPro, a Sun Microsystems, Inc. business.
  11  * Permission to use, copy, modify, and distribute this
  12  * software is freely granted, provided that this notice
  13  * is preserved.
  14  * ====================================================
  15  */
  16
  17 #ifndef INLINE_KERNEL_COSDF
  18 #ifndef lint
  19 static char rcsid[] = "$FreeBSD: src/lib/msun/src/k_cosf.c,v 1.15 2005/11/30 11:51:17 bde Exp $";
  20 #endif
  21 #endif
  22
  23 #include "math.h"
  24 #include "math_private.h"
  25
  26 /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
  27 static const double
  28 one =  1.0,
  29 C0  = -0x1ffffffd0c5e81.0p-54,  /* -0.499999997251031003120 */
  30 C1  =  0x155553e1053a42.0p-57,  /*  0.0416666233237390631894 */
  31 C2  = -0x16c087e80f1e27.0p-62,  /* -0.00138867637746099294692 */
  32 C3  =  0x199342e0ee5069.0p-68;  /*  0.0000243904487962774090654 */
  33
  34 #ifdef INLINE_KERNEL_COSDF
  35 static __inline
  36 #endif
  37 float
  38 __kernel_cosdf(double x)
  39 {
  40         double r, w, z;
  41
  42         /* Try to optimize for parallel evaluation as in k_tanf.c. */
  43         z  = x*x;
  44         w = z*z;
  45         r = C2+z*C3;
  46         return ((one+z*C0) + w*C1) + (w*z)*r;
  47 }