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[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libm/] [mathfp/] [sf_sineh.c] - Blame information for rev 842

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Line No. Rev Author Line
1 207 jeremybenn
 
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/* @(#)z_sinehf.c 1.0 98/08/13 */
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/******************************************************************
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 * The following routines are coded directly from the algorithms
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 * and coefficients given in "Software Manual for the Elementary
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 * Functions" by William J. Cody, Jr. and William Waite, Prentice
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 * Hall, 1980.
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 ******************************************************************/
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/******************************************************************
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 * Hyperbolic Sine
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 *
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 * Input:
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 *   x - floating point value
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 *
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 * Output:
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 *   hyperbolic sine of x
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 *
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 * Description:
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 *   This routine calculates hyperbolic sines.
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 *
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 *****************************************************************/
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#include <float.h>
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#include "fdlibm.h"
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#include "zmath.h"
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static const float q[] = { -0.428277109e+2 };
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static const float p[] = { -0.713793159e+1,
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                           -0.190333399 };
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static const float LNV = 0.6931610107;
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static const float INV_V2 = 0.2499930850;
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static const float V_OVER2_MINUS1 = 0.1383027787e-4;
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float
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_DEFUN (sinehf, (float, int),
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        float x _AND
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        int cosineh)
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{
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  float y, f, P, Q, R, res, z, w;
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  int sgn = 1;
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  float WBAR = 18.55;
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  /* Check for special values. */
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  switch (numtestf (x))
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    {
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      case NAN:
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        errno = EDOM;
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        return (x);
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      case INF:
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        errno = ERANGE;
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        return (ispos (x) ? z_infinity_f.f : -z_infinity_f.f);
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    }
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  y = fabs (x);
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  if (!cosineh && x < 0.0)
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    sgn = -1;
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  if ((y > 1.0 && !cosineh) || cosineh)
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    {
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      if (y > BIGX)
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        {
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          w = y - LNV;
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          /* Check for w > maximum here. */
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          if (w > BIGX)
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            {
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              errno = ERANGE;
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              return (x);
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            }
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          z = exp (w);
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          if (w > WBAR)
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            res = z * (V_OVER2_MINUS1 + 1.0);
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        }
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      else
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        {
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          z = exp (y);
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          if (cosineh)
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            res = (z + 1 / z) / 2.0;
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          else
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            res = (z - 1 / z) / 2.0;
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        }
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      if (sgn < 0)
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        res = -res;
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    }
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  else
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    {
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      /* Check for y being too small. */
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      if (y < z_rooteps_f)
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        {
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          res = x;
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        }
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      /* Calculate the Taylor series. */
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      else
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        {
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          f = x * x;
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          Q = f + q[0];
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          P = p[1] * f + p[0];
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          R = f * (P / Q);
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          res = x + x * R;
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        }
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    }
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  return (res);
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}

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