+
−/* s_sinl.c -- long double version of s_sin.c.
+
− * Conversion to long double by Jakub Jelinek, jj@ultra.linux.cz.
+
− */
+
−
+
−/*
+
− * ====================================================
+
− * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+
− *
+
− * Developed at SunPro, a Sun Microsystems, Inc. business.
+
− * Permission to use, copy, modify, and distribute this
+
− * software is freely granted, provided that this notice
+
− * is preserved.
+
− * ====================================================
+
− */
+
−
+
−#include <config.h>
+
−
+
−/* Specification.  */
+
−#include <math.h>
+
−
+
−#if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
+
−
+
−long double
+
−sinl (long double x)
+
−{
+
−  return sin (x);
+
−}
+
−
+
−#else
+
−
+
−/* Code based on glibc/sysdeps/ieee754/ldbl-128/s_sinl.c.  */
+
−
+
−/* sinl(x)
+
− * Return sine function of x.
+
− *
+
− * kernel function:
+
− *      __kernel_sinl           ... sine function on [-pi/4,pi/4]
+
− *      __kernel_cosl           ... cosine function on [-pi/4,pi/4]
+
− *      __ieee754_rem_pio2l     ... argument reduction routine
+
− *
+
− * Method.
+
− *      Let S,C and T denote the sin, cos and tan respectively on
+
− *      [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
+
− *      in [-pi/4 , +pi/4], and let n = k mod 4.
+
− *      We have
+
− *
+
− *          n        sin(x)      cos(x)        tan(x)
+
− *     ----------------------------------------------------------
+
− *          0          S           C             T
+
− *          1          C          -S            -1/T
+
− *          2         -S          -C             T
+
− *          3         -C           S            -1/T
+
− *     ----------------------------------------------------------
+
− *
+
− * Special cases:
+
− *      Let trig be any of sin, cos, or tan.
+
− *      trig(+-INF)  is NaN, with signals;
+
− *      trig(NaN)    is that NaN;
+
− *
+
− * Accuracy:
+
− *      TRIG(x) returns trig(x) nearly rounded
+
− */
+
−
+
−# include "trigl.h"
+
−
+
−long double
+
−sinl (long double x)
+
−{
+
−  long double y[2], z = 0.0L;
+
−  int n;
+
−
+
−  /* sinl(NaN) is NaN */
+
−  if (isnanl (x))
+
−    return x;
+
−
+
−  /* |x| ~< pi/4 */
+
−  if (x >= -0.7853981633974483096156608458198757210492
+
−      && x <= 0.7853981633974483096156608458198757210492)
+
−    return kernel_sinl (x, z, 0);
+
−
+
−    /* sinl(Inf) is NaN, sinl(0) is 0 */
+
−  else if (x + x == x)
+
−    return x - x;               /* NaN */
+
−
+
−  /* argument reduction needed */
+
−  else
+
−    {
+
−      n = ieee754_rem_pio2l (x, y);
+
−      switch (n & 3)
+
−        {
+
−        case 0:
+
−          return kernel_sinl (y[0], y[1], 1);
+
−        case 1:
+
−          return kernel_cosl (y[0], y[1]);
+
−        case 2:
+
−          return -kernel_sinl (y[0], y[1], 1);
+
−        default:
+
−          return -kernel_cosl (y[0], y[1]);
+
−        }
+
−    }
+
−}
+
−
+
−#endif
+
−
+
−#if 0
+
−int
+
−main (void)
+
−{
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *29));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *2));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *30));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *4));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *32));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *2/3));
+
−  printf ("%.16Lg\n", sinl (0.7853981633974483096156608458198757210492 *4/3));
+
−}
+
−#endif