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/* PROLOG END TAG zYx                                              */

#ifdef __SPU__

#ifndef _LOG1PF4_H_

#define _LOG1PF4_H_     1

#include <spu_intrinsics.h>

#include "simdmath.h"

#include "logf4.h"

#include "divf4.h"

/*

 * FUNCTION

 *      vector float _log1pf4(vector float x)

 *

 * DESCRIPTION

 *      The function _log1pf4 computes the natural logarithm of x + 1

 *      for each of the float word elements of x.

 *

 *

 */

#define LOG1PF4_P0 0.0000000000000000000000000e+00f

#define LOG1PF4_P1 1.0000000000000000000000000e+00f

#define LOG1PF4_P2 1.4220868022897381610647471e+00f

#define LOG1PF4_P3 5.4254553902256308361984338e-01f

#define LOG1PF4_P4 4.5971908823142115796400731e-02f

#define LOG1PF4_Q0 1.0000000000000000000000000e+00f

#define LOG1PF4_Q1 1.9220868007537357247116461e+00f

#define LOG1PF4_Q2 1.1702556461286610645089468e+00f

#define LOG1PF4_Q3 2.4040413392943396631018516e-01f

#define LOG1PF4_Q4 1.0637426466449625625521058e-02f

static __inline vector float _log1pf4(vector float x)

{

  vector float onef  = spu_splats(1.0f);

  vector float range = spu_splats(0.35f);

  vector unsigned int use_log;

  vector float pr, qr;

  vector float eresult;

  vector float rresult;

  vector float result;

  use_log = spu_cmpabsgt(x, range);

  /*

   * Calculate directly using log(x+1)

   */

  eresult = _logf4(spu_add(x, onef));

  /*

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

   */

  pr = spu_madd(x, spu_splats((float)LOG1PF4_P4), spu_splats((float)LOG1PF4_P3));

  qr = spu_madd(x, spu_splats((float)LOG1PF4_Q4), spu_splats((float)LOG1PF4_Q3));

  pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P2));

  qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q2));

  pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P1));

  qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q1));

  pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P0));

  qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q0));

  rresult = _divf4(pr, qr);

  /*

   * Select either direct calculation or rational approximation.

   */

  result = spu_sel(rresult, eresult, use_log);

  return result;

}

#endif /* _LOG1PF4_H_ */

#endif /* __SPU__ */