diff options
Diffstat (limited to 'Build/source/libs/gmp/gmp-6.0.0/mpn/generic/sec_tabselect.c')
-rw-r--r-- | Build/source/libs/gmp/gmp-6.0.0/mpn/generic/sec_tabselect.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/Build/source/libs/gmp/gmp-6.0.0/mpn/generic/sec_tabselect.c b/Build/source/libs/gmp/gmp-6.0.0/mpn/generic/sec_tabselect.c new file mode 100644 index 00000000000..7ea2ffda63b --- /dev/null +++ b/Build/source/libs/gmp/gmp-6.0.0/mpn/generic/sec_tabselect.c @@ -0,0 +1,55 @@ +/* mpn_sec_tabselect. + +Copyright 2007-2009, 2011, 2013 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + +or + + * the GNU General Public License as published by the Free Software + Foundation; either version 2 of the License, or (at your option) any + later version. + +or both in parallel, as here. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include "gmp.h" +#include "gmp-impl.h" + + +/* Select entry `which' from table `tab', which has nents entries, each `n' + limbs. Store the selected entry at rp. Reads entire table to avoid + side-channel information leaks. O(n*nents). */ +void +mpn_sec_tabselect (volatile mp_limb_t *rp, volatile const mp_limb_t *tab, + mp_size_t n, mp_size_t nents, mp_size_t which) +{ + mp_size_t k, i; + mp_limb_t mask; + volatile const mp_limb_t *tp; + + for (k = 0; k < nents; k++) + { + mask = -(mp_limb_t) (which == k); + tp = tab + n * k; + for (i = 0; i < n; i++) + { + rp[i] = (rp[i] & ~mask) | (tp[i] & mask); + } + } +} |