newlib-cygwin/newlib/libm/machine/spu/headers/asinhd2.h

164 lines
6.3 KiB
C

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/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _ASINHD2_H_
#define _ASINHD2_H_ 1
#include <spu_intrinsics.h>
#include "logd2.h"
#include "sqrtd2.h"
/*
* FUNCTION
* vector double _asinhd2(vector double x)
*
* DESCRIPTION
* The asinhd2 function returns a vector containing the hyperbolic
* arcsines of the corresponding elements of the input vector.
*
* We are using the formula:
* asinh = ln(|x| + sqrt(x^2 + 1))
* and the anti-symmetry of asinh.
*
* For x near zero, we use the Taylor series:
*
* infinity
* ------
* - ' P (0)
* - k-1 k
* asinh x = - ----- x
* - k
* - ,
* ------
* k = 1
*
* Special Cases:
* asinh(+0) returns +0
* asinh(-0) returns -0
* asinh(+infinity) returns +infinity
* asinh(-infinity) returns -infinity
* asinh(NaN) returns NaN
*
*/
/*
* Maclaurin Series Coefficients
* for x near 0.
*/
#define SDM_ASINHD2_MAC01 1.000000000000000000000000000000000000000000E0
#define SDM_ASINHD2_MAC03 -1.666666666666666666666666666666666666666667E-1
#define SDM_ASINHD2_MAC05 7.500000000000000000000000000000000000000000E-2
#define SDM_ASINHD2_MAC07 -4.464285714285714285714285714285714285714286E-2
#define SDM_ASINHD2_MAC09 3.038194444444444444444444444444444444444444E-2
#define SDM_ASINHD2_MAC11 -2.237215909090909090909090909090909090909091E-2
#define SDM_ASINHD2_MAC13 1.735276442307692307692307692307692307692308E-2
#define SDM_ASINHD2_MAC15 -1.396484375000000000000000000000000000000000E-2
#define SDM_ASINHD2_MAC17 1.155180089613970588235294117647058823529412E-2
static __inline vector double _asinhd2(vector double x)
{
vec_double2 sign_mask = spu_splats(-0.0);
vec_double2 oned = spu_splats(1.0);
vec_uchar16 dup_even = ((vec_uchar16) { 0,1,2,3, 0,1,2,3, 8,9,10,11, 8,9,10,11 });
vec_uint4 infminus1 = spu_splats(0x7FEFFFFFU);
vec_uint4 isinfnan;
vec_double2 xabs, xsqu;
vec_uint4 xabshigh;
vec_float4 switch_approx = spu_splats(0.165f); /* Where we switch from maclaurin to formula */
vec_uint4 use_form;
vec_float4 xf;
vec_double2 result, fresult, mresult;
xabs = spu_andc(x, sign_mask);
xsqu = spu_mul(x, x);
xf = spu_roundtf(xabs);
xf = spu_shuffle(xf, xf, dup_even);
/*
* Formula:
* asinh = ln(|x| + sqrt(x^2 + 1))
*/
fresult = _sqrtd2(spu_add(xsqu, oned));
fresult = spu_add(xabs, fresult);
fresult = _logd2(fresult);
/*
* Maclaurin Series approximation
*/
mresult = spu_splats(SDM_ASINHD2_MAC17);
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC15));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC13));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC11));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC09));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC07));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC05));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC03));
mresult = spu_madd(xsqu, mresult, spu_splats(SDM_ASINHD2_MAC01));
mresult = spu_mul(xabs, mresult);
/*
* Choose between series and formula
*/
use_form = spu_cmpgt(xf, switch_approx);
result = spu_sel(mresult, fresult, (vec_ullong2)use_form);
/* Special Cases */
/* Infinity and NaN */
xabshigh = (vec_uint4)spu_shuffle(xabs, xabs, dup_even);
isinfnan = spu_cmpgt(xabshigh, infminus1);
result = spu_sel(result, x, (vec_ullong2)isinfnan);
/* Restore sign - asinh is an anti-symmetric */
result = spu_sel(result, x, (vec_ullong2)sign_mask);
return result;
}
#endif /* _ASINHD2_H_ */
#endif /* __SPU__ */