96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
/*
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Copyright 2009 Jason Moxham
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This file is part of the MPIR Library.
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The MPIR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 2.1 of the License, or (at
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your option) any later version.
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The MPIR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the MPIR Library; see the file COPYING.LIB. If not, write
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to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#include "mpir.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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mp_limb_t mpn_divrem_hensel_rsh_qr_1_preinv(mp_ptr qp, mp_srcptr xp,
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mp_size_t n, mp_limb_t d, mp_limb_t m, int s)
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{
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mp_size_t j;
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mp_limb_t c, h, q, dummy, h1, t;
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ASSERT(n > 0);
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ASSERT(d%2 == 1);
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ASSERT_MPN(xp, n);
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ASSERT(MPN_SAME_OR_SEPARATE_P(qp, xp, n));
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ASSERT(s >= 0);
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c = 0;
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h = 0;
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t = 0;
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for (j = 0; j <= n - 2; j++)
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{
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h1 = (xp[j]>>s) | (xp[j + 1]<<(GMP_LIMB_BITS - 1 - s)<<1);
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t = h + c;
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if (t > h1)
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{
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h1 = h1 - t;
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c = 1;
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}
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else
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{
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h1 = h1 - t;
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c = 0;
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}
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q = h1*m;
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qp[j] = q;
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umul_ppmm(h, dummy, q, d);
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ASSERT(dummy == h1);
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}
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h1 = xp[n - 1]>>s;
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t = h + c;
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if (t > h1)
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{
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h1 = h1 - t;
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c = 1;
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}
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else
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{
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h1 = h1 - t;
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c = 0;
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}
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q = h1*m;
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qp[n - 1] = q;
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umul_ppmm(h, dummy, q, d);
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ASSERT(dummy == h1);
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return h + c;
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}
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mp_limb_t mpn_divrem_hensel_rsh_qr_1(mp_ptr qp, mp_srcptr xp,
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mp_size_t n, mp_limb_t d, int s)
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{
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mp_limb_t m;
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modlimb_invert(m, d); /* should we allow s=0 ?? */
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return mpn_divrem_hensel_rsh_qr_1_preinv(qp, xp, n, d, m, s);
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}
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