compiler/mlib/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  */
   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 #ifndef INLINE_KERNEL_COSDF
  17 #ifndef lint
  18 static char rcsid[] = "$FreeBSD: src/lib/msun/src/k_cosf.c,v 1.5 1999/08/28 00:06:40 peter Exp $";
  19 #endif
  20 #endif
  21
  22 #include "math.h"
  23 #include "math_private.h"
  24
  25 /* |cos(x) - c(x)| < 2**-34.1 (~[-5.37e-11, 5.295e-11]). */
  26 static const double
  27 one =  1.0,
  28 C0  = -0x1ffffffd0c5e81.0p-54,  /* -0.499999997251031003120 */
  29 C1  =  0x155553e1053a42.0p-57,  /*  0.0416666233237390631894 */
  30 C2  = -0x16c087e80f1e27.0p-62,  /* -0.00138867637746099294692 */
  31 C3  =  0x199342e0ee5069.0p-68;  /*  0.0000243904487962774090654 */
  32
  33 #ifdef INLINE_KERNEL_COSDF
  34 extern inline
  35 #endif
  36 float
  37 __kernel_cosdf(double x)
  38 {
  39         double r, w, z;
  40
  41         /* Try to optimize for parallel evaluation as in k_tanf.c. */
  42         z  = x*x;
  43         w = z*z;
  44         r = C2+z*C3;
  45         return ((one+z*C0) + w*C1) + (w*z)*r;
  46 }