Retro68/gcc/newlib/libm/machine/spu/headers/acoshf4.h
2012-03-27 01:51:53 +02:00

161 lines
7.6 KiB
C

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/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _ACOSHF4_H_
#define _ACOSHF4_H_ 1
#include <spu_intrinsics.h>
#include "logf4.h"
#include "sqrtf4.h"
/*
* FUNCTION
* vector float _acoshf4(vector float x)
*
* DESCRIPTION
* The acoshf4 function returns a vector containing the hyperbolic
* arccosines of the corresponding elements of the input vector.
*
* We are using the formula:
* acosh = ln(x + sqrt(x^2 - 1))
*
* For x near one, we use the Taylor series:
*
* infinity
* ------
* - '
* - k
* acosh x = - C (x - 1)
* - k
* - ,
* ------
* k = 0
*
*
* Special Cases:
* - acosh(1) = +0
* - NaNs and Infinity aren't supported for single-precision on SPU.
*
*/
/*
* Taylor Series Coefficients
* for x around 1.
*/
#define SDM_ACOSHF4_TAY01 1.00000000000000000000000000000000000E0f /* 1 / 1 */
#define SDM_ACOSHF4_TAY02 -8.33333333333333333333333333333333333E-2f /* 1 / 12 */
#define SDM_ACOSHF4_TAY03 1.87500000000000000000000000000000000E-2f /* 3 / 160 */
#define SDM_ACOSHF4_TAY04 -5.58035714285714285714285714285714286E-3f /* 5 / 896 */
#define SDM_ACOSHF4_TAY05 1.89887152777777777777777777777777778E-3f /* 35 / 18432 */
#define SDM_ACOSHF4_TAY06 -6.99129971590909090909090909090909091E-4f /* 63 / 90112 */
#define SDM_ACOSHF4_TAY07 2.71136944110576923076923076923076923E-4f /* 231 / 851968 */
#define SDM_ACOSHF4_TAY08 -1.09100341796875000000000000000000000E-4f /* 143 / 1310720 */
#define SDM_ACOSHF4_TAY09 4.51242222505457261029411764705882353E-5f /* 6435 / 142606336 */
#define SDM_ACOSHF4_TAY10 -1.90656436117071854440789473684210526E-5f /* 12155 / 637534208 */
#define SDM_ACOSHF4_TAY11 8.19368731407892136346726190476190476E-6f /* 46189 / 5637144576 */
#define SDM_ACOSHF4_TAY12 -3.57056927421818608823029891304347826E-6f /* 88179 / 24696061952 */
#define SDM_ACOSHF4_TAY13 1.57402595505118370056152343750000000E-6f /* 676039 / 429496729600 */
#define SDM_ACOSHF4_TAY14 -7.00688192241445735648826316550925926E-7f /* 1300075 / 1855425871872 */
#define SDM_ACOSHF4_TAY15 3.14533061665033215078814276333512931E-7f /* 5014575 / 15942918602752 */
#if 0
#define SDM_ACOSHF4_TAY16 -1.42216292935641362301764949675529234E-7f /* 9694845 / 68169720922112 */
#define SDM_ACOSHF4_TAY17 6.47111067761133282064375552264126864E-8f /* 100180065 / 1548112371908608 */
#define SDM_ACOSHF4_TAY18 -2.96094097811711825280716376645224435E-8f /* 116680311 / 3940649673949184 */
#define SDM_ACOSHF4_TAY19 1.36154380562817937676005090612011987E-8f /* 2268783825 / 166633186212708352 */
#endif
static __inline vector float _acoshf4(vector float x)
{
vec_float4 minus_onef = spu_splats(-1.0f);
vec_float4 twof = spu_splats(2.0f);
vec_float4 largef = spu_splats(2.5e19f);
vec_float4 xminus1;
/* Where we switch from taylor to formula */
vec_float4 switch_approx = spu_splats(2.0f);
vec_uint4 use_form;
vec_float4 result, fresult, mresult;;
/*
* Formula:
* acosh = ln(x + sqrt(x^2 - 1))
*/
fresult = _sqrtf4(spu_madd(x, x, minus_onef));
fresult = spu_add(x, spu_sel(fresult, x, spu_cmpgt(x, largef)));
fresult = _logf4(fresult);
fresult = (vec_float4)spu_add((vec_uint4)fresult, spu_splats(2u));
/*
* Taylor Series
*/
xminus1 = spu_add(x, minus_onef);
mresult = spu_splats(SDM_ACOSHF4_TAY15);
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY14));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY13));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY12));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY11));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY10));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY09));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY08));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY07));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY06));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY05));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY04));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY03));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY02));
mresult = spu_madd(xminus1, mresult, spu_splats(SDM_ACOSHF4_TAY01));
mresult = spu_mul(mresult, _sqrtf4(spu_mul(xminus1, twof)));
mresult = (vec_float4)spu_add((vec_uint4)mresult, spu_splats(1u));
/*
* Select series or formula
*/
use_form = spu_cmpgt(x, switch_approx);
result = spu_sel(mresult, fresult, use_form);
return result;
}
#endif /* _ACOSHF4_H_ */
#endif /* __SPU__ */