Retro68/gcc/newlib/libm/machine/spu/headers/tand2.h
2012-03-27 01:51:53 +02:00

106 lines
4.6 KiB
C

/* -------------------------------------------------------------- */
/* (C)Copyright 2001,2008, */
/* International Business Machines Corporation, */
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/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _TAND2_H_
#define _TAND2_H_ 1
#include <spu_intrinsics.h>
#include "cos_sin.h"
#include "divd2.h"
/*
* FUNCTION
* vector double _tand2(vector double angle)
*
* DESCRIPTION
* The _tand2 function computes the tangent of a vector of "angle"s
* (expressed in radians) to an accuracy of double precision floating
* point.
*
*/
static __inline vector double _tand2(vector double angle)
{
vec_int4 octant;
vec_ullong2 select;
vec_double2 cos, sin;
vec_double2 num, den;
vec_double2 toggle_sign, answer;
/* Range reduce the input angle x into the range -PI/4 to PI/4
* by performing simple modulus.
*/
MOD_PI_OVER_FOUR(angle, octant);
/* Compute the cosine and sine of the range reduced input.
*/
COMPUTE_COS_SIN(angle, cos, sin);
/* For each SIMD element, select the numerator, denominator, and sign
* correction depending upon the octant of the original angle.
*
* octants angles numerator denominator sign toggle
* ------- ------------ --------- ----------- -----------
* 0 0 to 45 sin cos no
* 1,2 45 to 135 cos sin no,yes
* 3,4 135 to 225 sin cos yes,no
* 5,6 225 to 315 cos sin no,yes
* 7 315 to 360 sin cos yes
*/
octant = spu_shuffle(octant, octant, ((vec_uchar16) {
0,1, 2, 3, 0,1, 2, 3,
8,9,10,11, 8,9,10,11 }));
toggle_sign = spu_and((vec_double2)spu_sl(octant, 30),
(vec_double2) spu_splats(0x8000000000000000ULL));
select = (vec_ullong2)spu_cmpeq(spu_and(octant, 2), 0);
num = spu_sel(cos, sin, select);
den = spu_sel(sin, cos, select);
answer = spu_xor(_divd2(num, den), toggle_sign);
return (answer);
}
#endif /* _TAND2_H_ */
#endif /* __SPU__ */