From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001 From: Duncan Wilkie Date: Sat, 18 Nov 2023 06:11:09 -0600 Subject: Initial commit. --- gmp-6.3.0/mpn/generic/cnd_add_n.c | 69 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 gmp-6.3.0/mpn/generic/cnd_add_n.c (limited to 'gmp-6.3.0/mpn/generic/cnd_add_n.c') diff --git a/gmp-6.3.0/mpn/generic/cnd_add_n.c b/gmp-6.3.0/mpn/generic/cnd_add_n.c new file mode 100644 index 0000000..e6b1373 --- /dev/null +++ b/gmp-6.3.0/mpn/generic/cnd_add_n.c @@ -0,0 +1,69 @@ +/* mpn_cnd_add_n -- Compute R = U + V if CND != 0 or R = U if CND == 0. + Both cases should take the same time and perform the exact same memory + accesses, since this function is intended to be used where side-channel + attack resilience is relevant. + +Copyright 1992-1994, 1996, 2000, 2002, 2008, 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-impl.h" + +mp_limb_t +mpn_cnd_add_n (mp_limb_t cnd, mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n) +{ + mp_limb_t ul, vl, sl, rl, cy, cy1, cy2, mask; + + ASSERT (n >= 1); + ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); + ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n)); + + mask = -(mp_limb_t) (cnd != 0); + cy = 0; + do + { + ul = *up++; + vl = *vp++ & mask; +#if GMP_NAIL_BITS == 0 + sl = ul + vl; + cy1 = sl < ul; + rl = sl + cy; + cy2 = rl < sl; + cy = cy1 | cy2; + *rp++ = rl; +#else + rl = ul + vl; + rl += cy; + cy = rl >> GMP_NUMB_BITS; + *rp++ = rl & GMP_NUMB_MASK; +#endif + } + while (--n != 0); + + return cy; +} -- cgit v1.2.3