sysdeps/ieee754/flt-32/k_sinf.c

   1 /* k_sinf.c -- float version of k_sin.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 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: k_sinf.c,v 1.4 1995/05/10 20:46:33 jtc Exp $";
  18 #endif
  19
  20 #include <float.h>
  21 #include <math.h>
  22 #include <math_private.h>
  23
  24 static const float
  25 half =  5.0000000000e-01,/* 0x3f000000 */
  26 S1  = -1.6666667163e-01, /* 0xbe2aaaab */
  27 S2  =  8.3333337680e-03, /* 0x3c088889 */
  28 S3  = -1.9841270114e-04, /* 0xb9500d01 */
  29 S4  =  2.7557314297e-06, /* 0x3638ef1b */
  30 S5  = -2.5050759689e-08, /* 0xb2d72f34 */
  31 S6  =  1.5896910177e-10; /* 0x2f2ec9d3 */
  32
  33 float __kernel_sinf(float x, float y, int iy)
  34 {
  35         float z,r,v;
  36         int32_t ix;
  37         GET_FLOAT_WORD(ix,x);
  38         ix &= 0x7fffffff;                       /* high word of x */
  39         if(ix<0x32000000)                       /* |x| < 2**-27 */
  40           {
  41             if (fabsf (x) < FLT_MIN)
  42               {
  43                 float force_underflow = x * x;
  44                 math_force_eval (force_underflow);
  45               }
  46             if ((int) x == 0)
  47               return x;         /* generate inexact */
  48           }
  49         z       =  x*x;
  50         v       =  z*x;
  51         r       =  S2+z*(S3+z*(S4+z*(S5+z*S6)));
  52         if(iy==0) return x+v*(S1+z*r);
  53         else      return x-((z*(half*y-v*r)-y)-v*S1);
  54 }