vasilito
facf0c92e0
Red Bear OS is a full fork. All sources must be available from git clone with zero network access. Removed gitignore rules that excluded fetched source trees under recipes/*/source/, local/recipes/kde/*/source/, local/recipes/qt/*/source/, and vendor source trees. Build artifacts (target/, build/, source.tar, *.o, *.so) remain excluded. 127291 files added — kernel, relibc, base, bootloader, pkgar, all KDE/Qt frameworks, mesa, wayland, DRM drivers, and every other recipe source.
135 lines
3.4 KiB
C
135 lines
3.4 KiB
C
/* mpn_sec_tabselect.
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Copyright 2007-2009, 2011, 2013, 2021 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 <stdio.h>
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#include "gmp-impl.h"
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#ifndef SEC_TABSELECT_METHOD
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#define SEC_TABSELECT_METHOD 1
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#endif
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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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#if SEC_TABSELECT_METHOD == 1
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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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tp = tab;
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/* Place first entry into result area. */
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for (i = 0; i < n; i++)
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rp[i] = tp[i];
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/* Conditionally replace entry in result area by entry 1...(nents-1) using
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masking trickery. */
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for (k = 1; k < nents; k++)
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{
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/* Generate a mask using an expression which all compilers should compile
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into branch-free code. The convoluted expression is designed to both
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allow mp_limb_t greater and mp_limb_t smaller than mp_size_t. */
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mask = -(mp_limb_t) ((-(unsigned long) (which ^ k)) >> (BITS_PER_ULONG - 1));
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tp += n;
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for (i = 0; i < n; i++)
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rp[i] = (rp[i] & mask) | (tp[i] & ~mask);
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}
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}
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#endif
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#if SEC_TABSELECT_METHOD == 2
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void
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mpn_sec_tabselect (volatile mp_limb_t * restrict rp,
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volatile const mp_limb_t * restrict 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, r0, r1, r2, r3;
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volatile const mp_limb_t * restrict tp;
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if (n & 1)
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{
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tp = tab;
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r0 = 0;
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for (k = 0; k < nents; k++)
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{
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mask = (mp_limb_t) ((-(unsigned long) (which ^ k)) >> (BITS_PER_ULONG - 1)) - 1;
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r0 += tp[0] & mask;
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tp += n;
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}
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rp[0] = r0;
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rp += 1;
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tab += 1;
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}
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if (n & 2)
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{
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tp = tab;
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r0 = r1 = 0;
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for (k = 0; k < nents; k++)
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{
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mask = (mp_limb_t) ((-(unsigned long) (which ^ k)) >> (BITS_PER_ULONG - 1)) - 1;
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r0 += tp[0] & mask;
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r1 += tp[1] & mask;
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tp += n;
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}
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rp[0] = r0;
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rp[1] = r1;
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rp += 2;
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tab += 2;
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}
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for (i = 0; i <= n - 4; i += 4)
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{
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tp = tab + i;
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r0 = r1 = r2 = r3 = 0;
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for (k = 0; k < nents; k++)
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{
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mask = (mp_limb_t) ((-(unsigned long) (which ^ k)) >> (BITS_PER_ULONG - 1)) - 1;
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r0 += tp[0] & mask;
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r1 += tp[1] & mask;
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r2 += tp[2] & mask;
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r3 += tp[3] & mask;
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tp += n;
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}
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rp[0] = r0;
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rp[1] = r1;
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rp[2] = r2;
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rp[3] = r3;
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rp += 4;
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}
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}
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#endif
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