142 lines
4.9 KiB
C
142 lines
4.9 KiB
C
/*
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(C) Copyright 2001,2006,
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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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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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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 names of the copyright holders nor the names of their
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contributors may be used to endorse or promote products derived from this
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software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _REMAINDERF_H_
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#define _REMAINDERF_H_ 1
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#include <spu_intrinsics.h>
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#include "headers/vec_literal.h"
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static __inline float _remainderf(float x, float y)
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{
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int n;
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vec_uint4 vx, vy, z;
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vec_uint4 abs_x, abs_y, abs_2x, abs_2y;
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vec_uint4 exp_x, exp_y;
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vec_uint4 zero_x, zero_y;
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vec_uint4 logb_x, logb_y;
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vec_uint4 mant_x, mant_y;
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vec_uint4 result, result0, resultx, cnt, sign, bias;
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vec_uint4 sign_mask = VEC_SPLAT_U32(0x80000000);
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vec_uint4 implied_1 = VEC_SPLAT_U32(0x00800000);
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vec_uint4 mant_mask = VEC_SPLAT_U32(0x007FFFFF);
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vec_float4 two = { 2.0f, 2.0f, 2.0f, 2.0f };
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vx = (vec_uint4)spu_promote(x, 0);
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vy = (vec_uint4)spu_promote(y, 0);
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abs_x = spu_andc(vx, sign_mask);
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abs_y = spu_andc(vy, sign_mask);
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abs_2y = spu_add(abs_y, implied_1); /* abs_2y = 2 * abs_y */
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sign = spu_and(vx, sign_mask);
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/* Compute abs_x = fmodf(abs_x, 2*abs_y). If y is greater than 0.5*SMAX
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* (SMAX is the maximum representable float), then return abs_x.
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*/
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{
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/* Determine ilogb of abs_x and abs_2y and
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* extract the mantissas (mant_x, mant_y)
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*/
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exp_x = spu_rlmask(abs_x, -23);
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exp_y = spu_rlmask(abs_2y, -23);
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resultx = spu_or(spu_cmpgt(abs_2y, abs_x), spu_cmpgt(abs_y, VEC_SPLAT_U32(0x7F7FFFFF)));
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zero_x = spu_cmpeq(exp_x, 0);
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zero_y = spu_cmpeq(exp_y, 0);
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logb_x = spu_add(exp_x, -127);
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logb_y = spu_add(exp_y, -127);
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mant_x = spu_andc(spu_sel(implied_1, abs_x, mant_mask), zero_x);
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mant_y = spu_andc(spu_sel(implied_1, abs_2y, mant_mask), zero_y);
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/* Compute fixed point fmod of mant_x and mant_y. Set the flag,
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* result0, to all ones if we detect that the final result is
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* ever 0.
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*/
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result0 = spu_or(zero_x, zero_y);
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n = spu_extract(spu_sub(logb_x, logb_y), 0);
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while (n-- > 0) {
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z = spu_sub(mant_x, mant_y);
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result0 = spu_or(spu_cmpeq(z, 0), result0);
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mant_x = spu_sel(spu_add(mant_x, mant_x), spu_add(z, z),
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spu_cmpgt((vec_int4)z, -1));
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}
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z = spu_sub(mant_x, mant_y);
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mant_x = spu_sel(mant_x, z, spu_cmpgt((vec_int4)z, -1));
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result0 = spu_or(spu_cmpeq(mant_x, 0), result0);
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/* Convert the result back to floating point and restore
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* the sign. If we flagged the result to be zero (result0),
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* zero it. If we flagged the result to equal its input x,
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* (resultx) then return x.
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*/
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cnt = spu_add(spu_cntlz(mant_x), -8);
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mant_x = spu_rl(spu_andc(mant_x, implied_1), (vec_int4)cnt);
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exp_y = spu_sub(exp_y, cnt);
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result0 = spu_orc(result0, spu_cmpgt((vec_int4)exp_y, 0)); /* zero denorm results */
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exp_y = spu_rl(exp_y, 23);
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result = spu_sel(exp_y, mant_x, mant_mask);
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abs_x = spu_sel(spu_andc(result, spu_rlmask(result0, -1)), abs_x, resultx);
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}
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/* if (2*x > y)
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* x -= y
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* if (2*x >= y) x -= y
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*/
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abs_2x = spu_add(abs_x, implied_1);
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bias = spu_cmpgt(abs_2x, abs_y);
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abs_x = spu_sel(abs_x, (vec_uint4)spu_sub((vec_float4)abs_x, (vec_float4)abs_y), bias);
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bias = spu_andc(bias, spu_rlmaska((vec_uint4)spu_msub((vec_float4)abs_x, two, (vec_float4)abs_y), -31));
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abs_x = spu_sel(abs_x, (vec_uint4)spu_sub((vec_float4)abs_x, (vec_float4)abs_y), bias);
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/* Generate a correct final sign
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*/
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result = spu_xor(abs_x, sign);
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return (spu_extract((vec_float4)result, 0));
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}
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#endif /* _REMAINDERF_H_ */
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