82 lines
1.9 KiB
C
82 lines
1.9 KiB
C
/* mpn_sub_n -- Subtract equal length limb vectors.
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Copyright 1992, 1993, 1994, 1996, 2000, 2002 Free Software 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., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "gmp.h"
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#include "gmp-impl.h"
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#if GMP_NAIL_BITS == 0
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mp_limb_t
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mpn_sub_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n)
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{
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mp_limb_t ul, vl, sl, rl, cy, cy1, cy2;
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ASSERT (n >= 1);
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ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n));
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ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n));
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cy = 0;
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do
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{
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ul = *up++;
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vl = *vp++;
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sl = ul - vl;
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cy1 = sl > ul;
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rl = sl - cy;
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cy2 = rl > sl;
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cy = cy1 | cy2;
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*rp++ = rl;
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}
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while (--n != 0);
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return cy;
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}
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#endif
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#if GMP_NAIL_BITS >= 1
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mp_limb_t
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mpn_sub_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n)
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{
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mp_limb_t ul, vl, rl, cy;
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ASSERT (n >= 1);
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ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n));
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ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n));
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cy = 0;
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do
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{
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ul = *up++;
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vl = *vp++;
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rl = ul - vl - cy;
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cy = rl >> (GMP_LIMB_BITS - 1);
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*rp++ = rl & GMP_NUMB_MASK;
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}
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while (--n != 0);
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return cy;
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}
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#endif
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