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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [newlib/] [libm/] [machine/] [spu/] [headers/] [remainder.h] - Blame information for rev 158

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1 148 jeremybenn
/*
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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 _REMAINDER_H_
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#define _REMAINDER_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 double _remainder(double x, double y)
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{
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  int n, shift;
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  vec_uchar16 swap_words = VEC_LITERAL(vec_uchar16, 4,5,6,7, 0,1,2,3, 12,13,14,15, 8,9,10,11);
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  vec_uchar16 propagate = VEC_LITERAL(vec_uchar16, 4,5,6,7, 192,192,192,192, 12,13,14,15, 192,192,192,192);
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  vec_uchar16 splat_hi = VEC_LITERAL(vec_uchar16, 0,1,2,3,0,1,2,3, 8,9,10,11, 8,9,10,11);
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  vec_uchar16 splat_lo = VEC_LITERAL(vec_uchar16, 4,5,6,7,4,5,6,7, 12,13,14,15, 12,13,14,15);
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  vec_uint4 vx, vy, z;
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  vec_uint4 x_hi, y_hi, y_lo;
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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 normal, norm, denorm;
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  vec_uint4 gt, eq, bias, y2_hi;
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  vec_uint4 nan_out;
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  vec_uint4 result, result0, resultx, cnt, sign, borrow;
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  vec_uint4 exp_special = VEC_SPLAT_U32(0x7FF00000);
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  vec_uint4 half_smax = VEC_SPLAT_U32(0x7FEFFFFF);
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  vec_uint4 lsb       = (vec_uint4)(VEC_SPLAT_U64(0x0000000000000001ULL));
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  vec_uint4 sign_mask = (vec_uint4)(VEC_SPLAT_U64(0x8000000000000000ULL));
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  vec_uint4 implied_1 = (vec_uint4)(VEC_SPLAT_U64(0x0010000000000000ULL));
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  vec_uint4 mant_mask = (vec_uint4)(VEC_SPLAT_U64(0x000FFFFFFFFFFFFFULL));
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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);
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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 (SMAX is the maximum
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   * representable float), then return abs_x.
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   */
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  {
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    x_hi = spu_shuffle(abs_x, abs_x, splat_hi);
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    y_lo = spu_shuffle(abs_y, abs_y, splat_lo);
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    y_hi = spu_shuffle(abs_y, abs_y, splat_hi);
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    y2_hi = spu_shuffle(abs_2y, abs_2y, splat_hi);
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    /* Force a NaN output if (1) abs_x is infinity or NaN or (2)
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     * abs_y is a NaN.
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     */
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    nan_out = spu_or(spu_cmpgt(x_hi, half_smax),
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                     spu_or(spu_cmpgt(y_hi, exp_special),
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                            spu_and(spu_cmpeq(y_hi, exp_special),
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                                    spu_cmpgt(y_lo, 0))));
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    /* Determine ilogb of abs_x and abs_y and
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     * extract the mantissas (mant_x, mant_y)
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     */
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    exp_x  = spu_rlmask(x_hi, -20);
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    exp_y  = spu_rlmask(y2_hi, -20);
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    resultx = spu_or(spu_cmpgt(y2_hi, x_hi), spu_cmpgt(y_hi, half_smax));
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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, -1023);
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    logb_y = spu_add(exp_y, -1023);
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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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      borrow = spu_genb(mant_x, mant_y);
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      borrow = spu_shuffle(borrow, borrow, propagate);
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      z = spu_subx(mant_x, mant_y, borrow);
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      result0 = spu_or(spu_cmpeq(spu_or(z, spu_shuffle(z, z, swap_words)), 0), result0);
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      mant_x = spu_sel(spu_slqw(mant_x, 1), spu_andc(spu_slqw(z, 1), lsb), spu_cmpgt((vec_int4)spu_shuffle(z, z, splat_hi), -1));
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    }
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    borrow = spu_genb(mant_x, mant_y);
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    borrow = spu_shuffle(borrow, borrow, propagate);
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    z = spu_subx(mant_x, mant_y, borrow);
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    mant_x = spu_sel(mant_x, z, spu_cmpgt((vec_int4)spu_shuffle(z, z, splat_hi), -1));
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    mant_x = spu_andc(mant_x, VEC_LITERAL(vec_uint4, 0,0,-1,-1));
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    result0 = spu_or(spu_cmpeq(spu_or(mant_x, spu_shuffle(mant_x, mant_x, swap_words)), 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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     * Double precision generates a denorm for an output.
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     */
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    cnt = spu_cntlz(mant_x);
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    cnt = spu_add(cnt, spu_and(spu_rlqwbyte(cnt, 4), spu_cmpeq(cnt, 32)));
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    cnt = spu_add(spu_shuffle(cnt, cnt, splat_hi), -11);
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    shift = spu_extract(exp_y, 0) - 1;
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    denorm = spu_slqwbytebc(spu_slqw(mant_x, shift), shift);
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    exp_y = spu_sub(exp_y, cnt);
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    normal = spu_cmpgt((vec_int4)exp_y, 0);
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    /* Normalize normal results, denormalize denorm results.
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     */
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    shift = spu_extract(cnt, 0);
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    norm = spu_slqwbytebc(spu_slqw(spu_andc(mant_x, VEC_LITERAL(vec_uint4, 0x00100000, 0, -1, -1)), shift), shift);
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    mant_x = spu_sel(denorm, norm, normal);
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    exp_y = spu_and(spu_rl(exp_y, 20), normal);
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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_and(spu_add(abs_x, implied_1), normal);
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  gt = spu_cmpgt(abs_2x, abs_y);
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  eq = spu_cmpeq(abs_2x, abs_y);
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  bias = spu_or(gt, spu_and(eq, spu_rlqwbyte(gt, 4)));
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  bias = spu_shuffle(bias, bias, splat_hi);
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  abs_x = spu_sel(abs_x, (vec_uint4)spu_sub((vec_double2)abs_x, (vec_double2)abs_y), bias);
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  bias = spu_andc(bias, spu_rlmaska((vec_uint4)spu_msub((vec_double2)abs_x, VEC_SPLAT_F64(2.0), (vec_double2)abs_y), -31));
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  bias = spu_shuffle(bias, bias, splat_hi);
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  abs_x = spu_sel(abs_x, (vec_uint4)spu_sub((vec_double2)abs_x, (vec_double2)abs_y), bias);
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  /* Generate a correct final sign
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   */
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  result = spu_sel(spu_xor(abs_x, sign), exp_special, nan_out);
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  return (spu_extract((vec_double2)result, 0));
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}
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#endif /* _REMAINDER_H_ */

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