modules/fdlibm/src/k_sinf.cpp

   1 /* k_sinf.c -- float version of k_sin.c
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  * 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_SINDF
  18 //#include <sys/cdefs.h>
  19 //__FBSDID("$FreeBSD$");
  20 #endif
  21
  22 #include "math_private.h"
  23
  24 /* |sin(x)/x - s(x)| < 2**-37.5 (~[-4.89e-12, 4.824e-12]). */
  25 static const double
  26 S1 = -0x15555554cbac77.0p-55,   /* -0.166666666416265235595 */
  27 S2 =  0x111110896efbb2.0p-59,   /*  0.0083333293858894631756 */
  28 S3 = -0x1a00f9e2cae774.0p-65,   /* -0.000198393348360966317347 */
  29 S4 =  0x16cd878c3b46a7.0p-71;   /*  0.0000027183114939898219064 */
  30
  31 #ifdef INLINE_KERNEL_SINDF
  32 static __inline
  33 #endif
  34 float
  35 __kernel_sindf(double x)
  36 {
  37         double r, s, w, z;
  38
  39         /* Try to optimize for parallel evaluation as in k_tanf.c. */
  40         z = x*x;
  41         w = z*z;
  42         r = S3+z*S4;
  43         s = z*x;
  44         return (x + s*(S1+z*S2)) + s*w*r;
  45 }