117 lines
4.6 KiB
C
117 lines
4.6 KiB
C
/*
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Copyright 2009, 2011 William Hart. All rights reserved.
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Redistribution and use in source and binary forms, with or without modification, are
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permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice, this list of
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conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice, this list
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of conditions and the following disclaimer in the documentation and/or other materials
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provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY William Hart ``AS IS'' AND ANY EXPRESS OR IMPLIED
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WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL William Hart OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF 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 SOFTWARE, EVEN IF
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ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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The views and conclusions contained in the software and documentation are those of the
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authors and should not be interpreted as representing official policies, either expressed
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or implied, of William Hart.
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*/
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#include "mpir.h"
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#include "gmp-impl.h"
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void butterfly_lshB(mp_ptr t, mp_ptr u, mp_ptr i1,
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mp_ptr i2, mp_size_t limbs, mp_size_t x, mp_size_t y)
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{
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mp_limb_t cy, cy1, cy2;
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if (x == 0)
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{
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if (y == 0)
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mpn_sumdiff_n(t + x, u + y, i1, i2, limbs + 1);
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else
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{
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cy = mpn_sumdiff_n(t, u + y, i1, i2, limbs - y);
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u[limbs] = -(cy&1);
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cy1 = cy>>1;
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cy = mpn_sumdiff_n(t + limbs - y, u, i2 + limbs - y, i1 + limbs - y, y);
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t[limbs] = cy>>1;
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mpn_add_1(t + limbs - y, t + limbs - y, y + 1, cy1);
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cy1 = -(cy&1) + (i2[limbs] - i1[limbs]);
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mpn_addmod_2expp1_1(u + y, limbs - y, cy1);
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cy1 = -(i1[limbs] + i2[limbs]);
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mpn_addmod_2expp1_1(t, limbs, cy1);
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}
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} else if (y == 0)
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{
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cy = mpn_sumdiff_n(t + x, u, i1, i2, limbs - x);
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t[limbs] = cy>>1;
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cy1 = cy&1;
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cy = mpn_sumdiff_n(t, u + limbs - x, i1 + limbs - x, i2 + limbs - x, x);
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cy2 = mpn_neg_n(t, t, x);
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u[limbs] = -(cy&1);
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mpn_sub_1(u + limbs - x, u + limbs - x, x + 1, cy1);
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cy1 = -(cy>>1) - cy2;
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cy1 -= (i1[limbs] + i2[limbs]);
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mpn_addmod_2expp1_1(t + x, limbs - x, cy1);
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cy1 = (i2[limbs] - i1[limbs]);
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mpn_addmod_2expp1_1(u, limbs, cy1);
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} else if (x > y)
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{
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cy = mpn_sumdiff_n(t + x, u + y, i1, i2, limbs - x);
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t[limbs] = cy>>1;
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cy1 = cy&1;
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cy = mpn_sumdiff_n(t, u + y + limbs - x, i1 + limbs - x, i2 + limbs - x, x - y);
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cy2 = mpn_neg_n(t, t, x - y);
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u[limbs] = -(cy&1);
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mpn_sub_1(u + y + limbs - x, u + y + limbs - x, x - y + 1, cy1);
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cy1 = (cy>>1) + cy2;
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cy = mpn_sumdiff_n(t + x - y, u, i2 + limbs - y, i1 + limbs - y, y);
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cy2 = mpn_neg_n(t + x - y, t + x - y, y);
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cy1 = -(cy>>1) - mpn_sub_1(t + x - y, t + x - y, y, cy1) - cy2;
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cy1 -= (i1[limbs] + i2[limbs]);
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mpn_addmod_2expp1_1(t + x, limbs - x, cy1);
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cy1 = -(cy&1) + (i2[limbs] - i1[limbs]);
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mpn_addmod_2expp1_1(u + y, limbs - y, cy1);
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} else if (x < y)
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{
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cy = mpn_sumdiff_n(t + x, u + y, i1, i2, limbs - y);
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u[limbs] = -(cy&1);
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cy1 = cy>>1;
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cy = mpn_sumdiff_n(t + x + limbs - y, u, i2 + limbs - y, i1 + limbs - y, y - x);
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t[limbs] = cy>>1;
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mpn_add_1(t + x + limbs - y, t + x + limbs - y, y - x + 1, cy1);
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cy1 = cy&1;
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cy = mpn_sumdiff_n(t, u + y - x, i2 + limbs - x, i1 + limbs - x, x);
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cy1 = -(cy&1) - mpn_sub_1(u + y - x, u + y - x, x, cy1);
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cy1 += (i2[limbs] - i1[limbs]);
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mpn_addmod_2expp1_1(u + y, limbs - y, cy1);
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cy2 = mpn_neg_n(t, t, x);
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cy1 = -(cy>>1) - (i1[limbs] + i2[limbs]) - cy2;
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mpn_addmod_2expp1_1(t + x, limbs - x, cy1);
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} else /* x == y */
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{
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cy = mpn_sumdiff_n(t + x, u + x, i1, i2, limbs - x);
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t[limbs] = cy>>1;
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u[limbs] = -(cy&1);
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cy = mpn_sumdiff_n(t, u, i2 + limbs - x, i1 + limbs - x, x);
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cy2 = mpn_neg_n(t, t, x);
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cy1 = -(cy>>1) - (i1[limbs] + i2[limbs]) - cy2;
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mpn_addmod_2expp1_1(t + x, limbs - x, cy1);
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cy1 = -(cy&1) + i2[limbs] - i1[limbs];
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mpn_addmod_2expp1_1(u + x, limbs - x, cy1);
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}
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}
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