7529cdb3f6
The upcoming vectormath that will used to speed up the SPU version of Extras/BulletMultiThreaded depends on this.
104 lines
4.0 KiB
C
104 lines
4.0 KiB
C
/* divi4 -
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Copyright (C) 2006, 2007 Sony Computer Entertainment Inc.
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All rights reserved.
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Redistribution and use in source and binary forms,
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with or without modification, are permitted provided that the
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following conditions are met:
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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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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the Sony Computer Entertainment Inc nor the names
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of its contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <simdmath.h>
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#include <altivec.h>
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#include "common-types.h"
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// divi4 - for each of four integer slots, compute quotient and remainder of numer/denom
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// and store in divi4_t struct. Divide by zero produces quotient = 0, remainder = numerator.
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divi4_t
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divi4 (vec_int4 numer, vec_int4 denom )
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{
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vec_int4 minusone = vec_splatsi4(-1);
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vec_uint4 zero = vec_splatsu4(0);
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vec_uint4 one = vec_splatsu4(1);
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vec_uint4 k158 = vec_splatsu4(158);
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vec_uint4 k23 = vec_splatsu4(23);
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divi4_t res;
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vec_uint4 numerPos, denomPos, quotNeg;
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vec_uint4 numerAbs, denomAbs;
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vec_uint4 denomZeros, numerZeros, shift, denomShifted, oneShifted;
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vec_uint4 quot, newQuot, skip, newNum, cont;
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int anyCont;
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// determine whether result needs sign change
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numerPos = (vec_uint4)vec_cmpgt( numer, minusone );
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denomPos = (vec_uint4)vec_cmpgt( denom, minusone );
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quotNeg = vec_xor( numerPos, denomPos );
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// use absolute values of numerator, denominator
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numerAbs = (vec_uint4)vec_sel( vec_sub( (vec_int4)zero, numer ), numer, numerPos );
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denomAbs = (vec_uint4)vec_sel( vec_sub( (vec_int4)zero, denom ), denom, denomPos );
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// get difference of leading zeros to align denom with numer
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denomZeros = vec_sub( k158, vec_sr( (vec_uint4)vec_ctf( denomAbs, 0 ), k23 ) );
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numerZeros = vec_sub( k158, vec_sr( (vec_uint4)vec_ctf( numerAbs, 0 ), k23 ) );
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shift = vec_sub( denomZeros, numerZeros );
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denomShifted = vec_sl( denomAbs, shift );
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oneShifted = vec_sl( one, shift );
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oneShifted = vec_sel( oneShifted, zero, vec_or( vec_cmpeq( denomAbs, zero ),
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vec_cmpgt( denomAbs, numerAbs ) ) );
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// long division
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quot = zero;
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do
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{
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cont = (vec_uint4)vec_cmpgt( oneShifted, zero );
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anyCont = vec_any_gt( oneShifted, zero );
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skip = (vec_uint4)vec_cmpgt( denomShifted, numerAbs );
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newQuot = vec_or( quot, oneShifted );
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newNum = vec_sub( numerAbs, denomShifted );
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oneShifted = vec_sr( oneShifted, one );
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denomShifted = vec_sr( denomShifted, one );
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quot = vec_sel( newQuot, quot, skip );
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numerAbs = vec_sel( numerAbs, newNum, vec_andc( cont, skip ) );
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}
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while ( anyCont );
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res.quot = (vec_int4)vec_sel( quot, vec_sub( zero, quot ), quotNeg );
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res.rem = (vec_int4)vec_sel( (vec_uint4)vec_sub( (vec_int4)zero, (vec_int4)numerAbs ), numerAbs, numerPos );
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return res;
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}
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