sinhf4.h

Newlib 嵌入式 C库 标准实现代码

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/* PROLOG END TAG zYx                                              */
#ifdef __SPU__
#ifndef _SINHF4_H_
#define _SINHF4_H_ 1

#include <spu_intrinsics.h>

#include "expf4.h"
#include "recipf4.h"


/*
 * FUNCTION
 *	vector float _sinhf4(vector float angle)
 *
 * DESCRIPTION
 *	The _sinhf4 function computes the hyperbolic sine of a vector of 
 *      angles (expressed in radians) to an accuracy of a single precision 
 *      floating point.
 *
 */
static __inline vector float _sinhf4(vector float x)
{
  //  1.0000  (above this number, use sinh(x) = 0.5 * (e^x - e^-x)
  vec_uint4 threshold = (vec_uint4)spu_splats(0x3F800000);

  vec_uint4 sign_mask = (vec_uint4)spu_splats(0x80000000);

  // Coefficents for the Taylor series
  vec_float4 f03 = spu_splats(1.6666666666666667E-1f); // 1/3!
  vec_float4 f05 = spu_splats(8.3333333333333333E-3f); // 1/5!
  vec_float4 f07 = spu_splats(1.9841269841269841E-4f); // 1/7!
  vec_float4 f09 = spu_splats(2.7557319223985891E-6f); // 1/9!
  vec_float4 f11 = spu_splats(2.5052108385441719E-8f); // 1/11!


  // Perform the calculation as a Taylor series
  vec_float4 result;
  vec_float4 x2 = spu_mul(x,x);
  result = spu_madd(x2,f11,f09);
  result = spu_madd(x2,result,f07);
  result = spu_madd(x2,result,f05);
  result = spu_madd(x2,result,f03);
  result = spu_madd(x2,result,spu_splats(1.0f));
  result = spu_mul(x,result);


  //  Perform calculation as a function of 0.5 * (e^x - e^-x)
  vec_float4 ex =_expf4(x);
  vec_float4 ex_inv = _recipf4(ex);

  vec_float4 r2= spu_sub(ex,ex_inv);
  r2 = spu_mul(r2,spu_splats(0.5f));

  vec_uint4 xabs = spu_andc((vec_uint4)x,sign_mask);
  vec_uint4 use_exp = spu_cmpgt(xabs,threshold);

  //  Select either the Taylor or exp version
  result = spu_sel(result,r2,use_exp);

  //  Flip the sign if needed
  result = (vec_float4)spu_or((vec_uint4)result,spu_and((vec_uint4)x,sign_mask));

  return result;  

}
#endif /* _SINHF4_H_ */
#endif /* __SPU__ */