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/* -------------------------------------------------------------- */
/* (C)Copyright 2001,2008, */
/* International Business Machines Corporation, */
/* Sony Computer Entertainment, Incorporated, */
/* Toshiba Corporation, */
/* */
/* All Rights Reserved. */
/* */
/* Redistribution and use in source and binary forms, with or */
/* without modification, are permitted provided that the */
/* following conditions are met: */
/* */
/* - Redistributions of source code must retain the above copyright*/
/* notice, this list of conditions and the following disclaimer. */
/* */
/* - Redistributions in binary form must reproduce the above */
/* copyright notice, this list of conditions and the following */
/* disclaimer in the documentation and/or other materials */
/* provided with the distribution. */
/* */
/* - Neither the name of IBM Corporation nor the names of its */
/* contributors may be used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* */
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/* -------------------------------------------------------------- */
/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _POWD2_H_
#define _POWD2_H_ 1
#include "exp2d2.h"
#include "log2d2.h"
/*
* FUNCTION
* vector double _powd2(vector double x, vector double y)
*
* DESCRIPTION
* The _powd2 function computes x raised to the power y for the set of
* vectors. The powd2 function is computed as by decomposing
* the problem into:
*
* x^y = 2^(y*log2(x))
*
*
*/
static __inline vector double _powd2(vector double x, vector double y)
{
vec_uchar16 splat_hi = (vec_uchar16) { 0,1,2,3,0,1,2,3, 8,9,10,11, 8,9,10,11 };
vec_int4 exp, shift;
vec_uint4 sign = (vec_uint4) { 0x80000000, 0, 0x80000000, 0 };
vec_uint4 or_mask, and_mask, evenmask, intmask;
vec_double2 in_hi;
vector double signmask = spu_splats(-0.0);
vector signed int error = spu_splats(-1);
vector double zero = spu_splats(0.0);
vector unsigned int y_is_int, y_is_odd, y_is_even;
vector unsigned int x_is_neg;
vector double xabs, xsign;
vector double out;
xsign = spu_and(x, signmask);
xabs = spu_andc(x, signmask);
x_is_neg = (vec_uint4)spu_cmpgt(zero, x);
/* First we solve assuming x was non-negative */
out = _exp2d2(spu_mul(y, _log2d2(xabs)));
in_hi = spu_shuffle(y, y, splat_hi);
exp = spu_and(spu_rlmask((vec_int4)in_hi, -20), 0x7FF);
/* Determine if y is an integer */
shift = spu_sub(((vec_int4) { 1023, 1043, 1023, 1043 }), exp);
or_mask = spu_andc(spu_cmpgt(shift, 0), sign);
and_mask = spu_rlmask(((vec_uint4) { 0xFFFFF, -1, 0xFFFFF, -1 }), shift);
intmask = spu_or(spu_and(and_mask, spu_cmpgt(shift, -32)), or_mask);
y_is_int = (vec_uint4)spu_cmpeq(y, spu_andc(y, (vec_double2)(intmask)));
/* Determine if y is an even integer */
shift = spu_sub(((vec_int4) { 1024, 1044, 1024, 1044 }), exp);
or_mask = spu_andc(spu_cmpgt(shift, 0), sign);
and_mask = spu_rlmask(((vec_uint4) { 0xFFFFF, -1, 0xFFFFF, -1 }), shift);
evenmask = spu_or(spu_and(and_mask, spu_cmpgt(shift, -32)), or_mask);
y_is_even = (vec_uint4)spu_cmpeq(y, spu_andc(y, (vec_double2)(evenmask)));
y_is_odd = spu_andc(y_is_int, y_is_even);
/* Special Cases
*/
/* x < 0 is only ok when y integer */
out = spu_sel(out, (vec_double2)error, (vec_ullong2)spu_andc(x_is_neg, y_is_int));
/* Preserve the sign of x if y is an odd integer */
out = spu_sel(out, spu_or(out, xsign), (vec_ullong2)y_is_odd);
/* x = anything, y = +/- 0, returns 1 */
out = spu_sel(out, spu_splats(1.0), spu_cmpabseq(y, zero));
return(out);
}
#endif /* _POWD2_H_ */
#endif /* __SPU__ */
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