50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
/* mpn_redc_1
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Copyright 1991, 1993, 1994, 1996, 1997, 2000, 2001, 2002, 2005 Free Software
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Foundation, Inc. Contributed by Paul Zimmermann.
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This file is part of the GNU MP Library.
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The GNU MP 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 by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP 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 GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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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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/* Set cp[] <- tp[]/R^n mod mp[]. Clobber tp[].
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mp[] is n limbs; tp[] is 2n limbs. */
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void mpn_redc_1 (mp_ptr cp, mp_ptr tp, mp_srcptr mp, mp_size_t n, mp_limb_t Nprim)
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{
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mp_limb_t cy;
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mp_limb_t q;
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mp_size_t j;
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ASSERT_MPN (tp, 2*n);
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for (j = 0; j < n; j++)
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{
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q = (tp[0] * Nprim) & GMP_NUMB_MASK;
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tp[0] = mpn_addmul_1 (tp, mp, n, q);
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tp++;
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}
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cy = mpn_add_n (cp, tp, tp - n, n);
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if (cy != 0)
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mpn_sub_n (cp, cp, mp, n);
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}
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