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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 _POWF4_H_
#define _POWF4_H_ 1
#include <spu_intrinsics.h>
#include <vec_types.h>
#include "exp2f4.h"
#include "log2f4.h"
/*
* FUNCTION
* vector float _powf4(vector float x, vector float y)
*
* DESCRIPTION
* The _powf4 function computes x raised to the power y for the set of
* vectors. The powf4 function is computed as by decomposing
* the problem into:
*
* x^y = 2^(y*log2(x))
*
*/
static __inline vector float _powf4(vector float x, vector float y)
{
vec_uint4 y_exp;
vec_uint4 y_mantissa;
vec_uint4 mant_shift;
vec_uint4 y_is_int;
vec_uint4 y_is_odd;
vec_uint4 x_sign_bit;
vec_uint4 zero = (vec_uint4)spu_splats(0);
vec_uint4 bit0 = (vec_uint4)spu_splats(0x80000000);
vec_int4 error = spu_splats(-1);
vec_float4 out;
y_exp = spu_and(spu_rlmask((vec_uint4)y, -23), 0x000000FF);
/* Need the implied bit in the mantissa to catch
* y = 1 case later
*/
y_mantissa = spu_or(spu_sl((vec_uint4)y, (unsigned int)8), bit0);
x_sign_bit = spu_and((vec_uint4)x, bit0);
/* We are going to shift the mantissa over enough to
* determine if we have an integer.
*/
mant_shift = spu_add(y_exp, -127);
/* Leave the lowest-order integer bit of mantissa on the
* high end so we can see if the integer is odd.
*/
y_mantissa = spu_sl(y_mantissa, mant_shift);
y_is_int = spu_cmpeq(spu_andc(y_mantissa, bit0), 0);
y_is_int = spu_and(y_is_int, spu_cmpgt(y_exp, 126));
y_is_odd = spu_and(spu_cmpeq(y_mantissa, bit0), y_is_int);
out = _exp2f4(spu_mul(y, _log2f4(spu_andc(x, (vec_float4)bit0))));
/* x < 0 is only ok when y integer
*/
out = spu_sel(out, (vec_float4)error,
spu_andc(spu_cmpeq(x_sign_bit, bit0), y_is_int));
/* Preserve the sign of x if y is an odd integer
*/
out = spu_sel(out, spu_or(out, (vec_float4)x_sign_bit), y_is_odd);
/* x = anything, y = +/- 0, returns 1
*/
out = spu_sel(out, spu_splats(1.0f), spu_cmpabseq(y, (vec_float4)zero));
return(out);
}
#endif /* _POWF4_H_ */
#endif /* __SPU__ */
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