mirror of https://github.com/macssh/macssh.git
84 lines
2.2 KiB
C
84 lines
2.2 KiB
C
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/* mpn_sqr_basecase -- Internal routine to square 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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#include "longlong.h"
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void
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#if __STDC__
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mpn_sqr_basecase (mp_ptr prodp, mp_srcptr up, mp_size_t n)
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#else
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mpn_sqr_basecase (prodp, up, n)
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mp_ptr prodp;
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mp_srcptr up;
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mp_size_t n;
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#endif
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{
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mp_size_t i;
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{
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/* N.B.! We need the superfluous indirection through argh to work around
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a reloader bug in GCC 2.7.*. */
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mp_limb_t x;
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mp_limb_t argh;
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x = up[0];
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umul_ppmm (argh, prodp[0], x, x);
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prodp[1] = argh;
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}
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if (n > 1)
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{
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mp_limb_t tarr[2 * KARATSUBA_SQR_THRESHOLD];
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mp_ptr tp = tarr;
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mp_limb_t cy;
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/* must fit 2*n limbs in tarr */
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ASSERT (n <= KARATSUBA_SQR_THRESHOLD);
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cy = mpn_mul_1 (tp, up + 1, n - 1, up[0]);
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tp[n - 1] = cy;
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for (i = 2; i < n; i++)
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{
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mp_limb_t cy;
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cy = mpn_addmul_1 (tp + 2 * i - 2, up + i, n - i, up[i - 1]);
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tp[n + i - 2] = cy;
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}
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for (i = 1; i < n; i++)
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{
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mp_limb_t x;
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x = up[i];
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umul_ppmm (prodp[2 * i + 1], prodp[2 * i], x, x);
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}
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{
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mp_limb_t cy;
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cy = mpn_lshift (tp, tp, 2 * n - 2, 1);
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cy += mpn_add_n (prodp + 1, prodp + 1, tp, 2 * n - 2);
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prodp[2 * n - 1] += cy;
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}
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}
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}
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