Retro68/gcc/newlib/libm/machine/spu/headers/coshf4.h
2012-03-27 01:51:53 +02:00

101 lines
4.3 KiB
C

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/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _COSHF4_H_
#define _COSHF4_H_ 1
#include <spu_intrinsics.h>
#include "expf4.h"
#include "recipf4.h"
/*
* FUNCTION
* vector float _coshf4(vector float x)
*
* DESCRIPTION
* The _coshf4 function computes the hyperbolic cosines of a vector of
* angles (expressed in radians) to an accuracy of a single precision
* floating point.
*
*/
static __inline vector float _coshf4(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 f02 = spu_splats(5.0000000000000000E-1f); // 1/2!
vec_float4 f04 = spu_splats(4.1666666666666667E-2f); // 1/4!
vec_float4 f06 = spu_splats(1.3888888888888889E-3f); // 1/6!
vec_float4 f08 = spu_splats(2.4801587301587302E-5f); // 1/8!
vec_float4 f10 = spu_splats(2.7557319223985891E-7f); // 1/10!
vec_float4 f12 = spu_splats(2.0876756987868099E-9f); // 1/12!
// Perform the calculation as a Taylor series
vec_float4 result;
vector float x2 = spu_mul(x,x);
result = spu_madd(x2,f12,f10);
result = spu_madd(x2,result,f08);
result = spu_madd(x2,result,f06);
result = spu_madd(x2,result,f04);
result = spu_madd(x2,result,f02);
result = spu_madd(x2,result,spu_splats(1.0f));
// 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_add(ex,ex_inv);
r2 = spu_mul(r2,f02); // we can reused f02 here
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);
return result;
}
#endif /* _COSHF4_H_ */
#endif /* __SPU__ */