Subversion Repositories openrisc_2011-10-31

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/* PROLOG END TAG zYx                                              */

#ifdef __SPU__

#ifndef _LOG1PD2_H_

#define _LOG1PD2_H_     1

#include <spu_intrinsics.h>

#include "simdmath.h"

#include "logd2.h"

#include "divd2.h"

#define LOG1PD2_P0 0.0000000000000000000000000e+00

#define LOG1PD2_P1 1.0000000000000000000000000e+00

#define LOG1PD2_P2 2.3771612265431403265836252e+00

#define LOG1PD2_P3 2.0034423569559494104908026e+00

#define LOG1PD2_P4 7.1309327316770110272159400e-01

#define LOG1PD2_P5 9.8219761968547217301228613e-02

#define LOG1PD2_P6 3.4385125174546914139650511e-03

#define LOG1PD2_Q0 1.0000000000000000000000000e+00

#define LOG1PD2_Q1 2.8771612265431403265836252e+00

#define LOG1PD2_Q2 3.1086896368941925317130881e+00

#define LOG1PD2_Q3 1.5583843494335058998956356e+00

#define LOG1PD2_Q4 3.6047236436186669283898709e-01

#define LOG1PD2_Q5 3.2620075387969869884496887e-02

#define LOG1PD2_Q6 6.8047193336239690346356479e-04

/*

 * FUNCTION

 *      vector double _log1pd2(vector double x)

 *

 * DESCRIPTION

 *      The function _log1pd2 computes the natural logarithm of x + 1

 *      for each of the double word elements of x.

 *

 */

static __inline vector double _log1pd2(vector double x)

{

  vector double oned  = spu_splats(1.0);

  vector double rangehi = spu_splats(0.35);

  vector double rangelo = spu_splats(0.0);

  vector unsigned long long use_log;

  vector double pr, qr;

  vector double eresult;

  vector double rresult;

  vector double result;

  /* Compiler Bug. Replace xbug with x when spu_cmp*() doesn't

   * modify it's arguments! */

  volatile vector double xbug = x;

  use_log = spu_or(spu_cmpgt(xbug, rangehi), spu_cmpgt(rangelo, xbug));

  /*

   * Calculate directly using log(x+1)

   */

  eresult = _logd2(spu_add(x, oned));

  /*

   * For x in [0.0,0.35], use a rational approximation.

   */

  pr = spu_madd(x, spu_splats(LOG1PD2_P6), spu_splats(LOG1PD2_P5));

  qr = spu_madd(x, spu_splats(LOG1PD2_Q6), spu_splats(LOG1PD2_Q5));

  pr = spu_madd(pr, x, spu_splats(LOG1PD2_P4));

  qr = spu_madd(qr, x, spu_splats(LOG1PD2_Q4));

  pr = spu_madd(pr, x, spu_splats(LOG1PD2_P3));

  qr = spu_madd(qr, x, spu_splats(LOG1PD2_Q3));

  pr = spu_madd(pr, x, spu_splats(LOG1PD2_P2));

  qr = spu_madd(qr, x, spu_splats(LOG1PD2_Q2));

  pr = spu_madd(pr, x, spu_splats(LOG1PD2_P1));

  qr = spu_madd(qr, x, spu_splats(LOG1PD2_Q1));

  pr = spu_madd(pr, x, spu_splats(LOG1PD2_P0));

  qr = spu_madd(qr, x, spu_splats(LOG1PD2_Q0));

  rresult = _divd2(pr, qr);

  /*

   * Select either direct calculation or rational approximation.

   */

  result = spu_sel(rresult, eresult, use_log);

  return result;

}

#endif /* _LOG1PD2_H_ */

#endif /* __SPU__ */