mirror of https://github.com/macssh/macssh.git
88 lines
2.7 KiB
C
Executable File
88 lines
2.7 KiB
C
Executable File
/* mpn_mul_basecase -- Internal routine to multiply two natural numbers
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of length m and n.
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THIS IS AN INTERNAL FUNCTION WITH A MUTABLE INTERFACE. IT IS ONLY
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SAFE TO REACH THIS FUNCTION THROUGH DOCUMENTED INTERFACES.
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Copyright (C) 1991, 1992, 1993, 1994, 1996, 1997, 2000 Free Software
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Foundation, Inc.
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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., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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/* Handle simple cases with traditional multiplication.
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This is the most critical code of multiplication. All multiplies rely on
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this, both small and huge. Small ones arrive here immediately, huge ones
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arrive here as this is the base case for Karatsuba's recursive algorithm. */
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void
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#if __STDC__
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mpn_mul_basecase (mp_ptr prodp,
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mp_srcptr up, mp_size_t usize,
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mp_srcptr vp, mp_size_t vsize)
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#else
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mpn_mul_basecase (prodp, up, usize, vp, vsize)
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mp_ptr prodp;
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mp_srcptr up;
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mp_size_t usize;
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mp_srcptr vp;
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mp_size_t vsize;
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#endif
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{
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/* We first multiply by the low order one or two limbs, as the result can
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be stored, not added, to PROD. We also avoid a loop for zeroing this
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way. */
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#if HAVE_NATIVE_mpn_mul_2
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if (vsize >= 2)
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{
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prodp[usize + 1] = mpn_mul_2 (prodp, up, usize, vp[0], vp[1]);
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prodp += 2, vp += 2, vsize -= 2;
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}
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else
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{
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prodp[usize] = mpn_mul_1 (prodp, up, usize, vp[0]);
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return;
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}
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#else
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prodp[usize] = mpn_mul_1 (prodp, up, usize, vp[0]);
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prodp += 1, vp += 1, vsize -= 1;
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#endif
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#if HAVE_NATIVE_mpn_addmul_2
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while (vsize >= 2)
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{
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prodp[usize + 1] = mpn_addmul_2 (prodp, up, usize, vp[0], vp[1]);
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prodp += 2, vp += 2, vsize -= 2;
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}
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if (vsize != 0)
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prodp[usize] = mpn_addmul_1 (prodp, up, usize, vp[0]);
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#else
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/* For each iteration in the loop, multiply U with one limb from V, and
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add the result to PROD. */
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while (vsize != 0)
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{
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prodp[usize] = mpn_addmul_1 (prodp, up, usize, vp[0]);
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prodp += 1, vp += 1, vsize -= 1;
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}
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#endif
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}
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