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4c74403188
Change-Id: Iae65e95cfa0d92091b8b0a424ae36d88efa76aa9 Reviewed-on: https://review.haiku-os.org/c/buildtools/+/3020 Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
/* mpn_sec_tabselect.
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Copyright 2007-2009, 2011, 2013 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 either:
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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or
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* the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any
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later version.
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or both in parallel, as here.
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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 General Public License
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for more details.
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You should have received copies of the GNU General Public License and the
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GNU Lesser General Public License along with the GNU MP Library. If not,
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see https://www.gnu.org/licenses/. */
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#include "gmp-impl.h"
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/* Select entry `which' from table `tab', which has nents entries, each `n'
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limbs. Store the selected entry at rp. Reads entire table to avoid
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side-channel information leaks. O(n*nents). */
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void
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mpn_sec_tabselect (volatile mp_limb_t *rp, volatile const mp_limb_t *tab,
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mp_size_t n, mp_size_t nents, mp_size_t which)
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{
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mp_size_t k, i;
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mp_limb_t mask;
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volatile const mp_limb_t *tp;
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for (k = 0; k < nents; k++)
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{
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mask = -(mp_limb_t) (which == k);
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tp = tab + n * k;
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for (i = 0; i < n; i++)
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{
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rp[i] = (rp[i] & ~mask) | (tp[i] & mask);
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}
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}
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}
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