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https://github.com/autc04/Retro68.git
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122 lines
5.2 KiB
C
122 lines
5.2 KiB
C
/* -------------------------------------------------------------- */
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/* (C)Copyright 2001,2008, */
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/* International Business Machines Corporation, */
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/* Sony Computer Entertainment, Incorporated, */
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/* Toshiba Corporation, */
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/* */
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/* All Rights Reserved. */
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/* */
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/* Redistribution and use in source and binary forms, with or */
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/* without modification, are permitted provided that the */
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/* following conditions are met: */
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/* */
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/* - Redistributions of source code must retain the above copyright*/
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/* notice, this list of conditions and the following disclaimer. */
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/* */
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/* - Redistributions in binary form must reproduce the above */
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/* copyright notice, this list of conditions and the following */
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/* disclaimer in the documentation and/or other materials */
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/* provided with the distribution. */
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/* */
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/* - Neither the name of IBM Corporation nor the names of its */
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/* contributors may be used to endorse or promote products */
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/* derived from this software without specific prior written */
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/* permission. */
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/* */
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/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
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/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
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/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
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/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
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/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
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/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
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/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
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/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
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/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
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/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
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/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
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/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
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/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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/* -------------------------------------------------------------- */
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/* PROLOG END TAG zYx */
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#ifdef __SPU__
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#ifndef _POWD2_H_
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#define _POWD2_H_ 1
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#include "exp2d2.h"
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#include "log2d2.h"
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/*
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* FUNCTION
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* vector double _powd2(vector double x, vector double y)
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*
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* DESCRIPTION
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* The _powd2 function computes x raised to the power y for the set of
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* vectors. The powd2 function is computed as by decomposing
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* the problem into:
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*
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* x^y = 2^(y*log2(x))
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*
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*
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*/
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static __inline vector double _powd2(vector double x, vector double y)
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{
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vec_uchar16 splat_hi = (vec_uchar16) { 0,1,2,3,0,1,2,3, 8,9,10,11, 8,9,10,11 };
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vec_int4 exp, shift;
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vec_uint4 sign = (vec_uint4) { 0x80000000, 0, 0x80000000, 0 };
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vec_uint4 or_mask, and_mask, evenmask, intmask;
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vec_double2 in_hi;
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vector double signmask = spu_splats(-0.0);
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vector signed int error = spu_splats(-1);
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vector double zero = spu_splats(0.0);
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vector unsigned int y_is_int, y_is_odd, y_is_even;
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vector unsigned int x_is_neg;
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vector double xabs, xsign;
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vector double out;
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xsign = spu_and(x, signmask);
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xabs = spu_andc(x, signmask);
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x_is_neg = (vec_uint4)spu_cmpgt(zero, x);
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/* First we solve assuming x was non-negative */
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out = _exp2d2(spu_mul(y, _log2d2(xabs)));
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in_hi = spu_shuffle(y, y, splat_hi);
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exp = spu_and(spu_rlmask((vec_int4)in_hi, -20), 0x7FF);
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/* Determine if y is an integer */
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shift = spu_sub(((vec_int4) { 1023, 1043, 1023, 1043 }), exp);
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or_mask = spu_andc(spu_cmpgt(shift, 0), sign);
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and_mask = spu_rlmask(((vec_uint4) { 0xFFFFF, -1, 0xFFFFF, -1 }), shift);
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intmask = spu_or(spu_and(and_mask, spu_cmpgt(shift, -32)), or_mask);
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y_is_int = (vec_uint4)spu_cmpeq(y, spu_andc(y, (vec_double2)(intmask)));
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/* Determine if y is an even integer */
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shift = spu_sub(((vec_int4) { 1024, 1044, 1024, 1044 }), exp);
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or_mask = spu_andc(spu_cmpgt(shift, 0), sign);
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and_mask = spu_rlmask(((vec_uint4) { 0xFFFFF, -1, 0xFFFFF, -1 }), shift);
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evenmask = spu_or(spu_and(and_mask, spu_cmpgt(shift, -32)), or_mask);
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y_is_even = (vec_uint4)spu_cmpeq(y, spu_andc(y, (vec_double2)(evenmask)));
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y_is_odd = spu_andc(y_is_int, y_is_even);
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/* Special Cases
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*/
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/* x < 0 is only ok when y integer */
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out = spu_sel(out, (vec_double2)error, (vec_ullong2)spu_andc(x_is_neg, y_is_int));
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/* Preserve the sign of x if y is an odd integer */
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out = spu_sel(out, spu_or(out, xsign), (vec_ullong2)y_is_odd);
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/* x = anything, y = +/- 0, returns 1 */
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out = spu_sel(out, spu_splats(1.0), spu_cmpabseq(y, zero));
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return(out);
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}
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#endif /* _POWD2_H_ */
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#endif /* __SPU__ */
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