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mpi-genesis             1 /* mpihelp-add_1.c  -  MPI helper functions
mpi_second_cut 2 * Modified by No Such Labs. (C) 2015. See README.
mpi-genesis 3 *
mpi_second_cut 4 * This file was originally part of Gnu Privacy Guard (GPG), ver. 1.4.10,
mpi_second_cut 5 * SHA256(gnupg-1.4.10.tar.gz):
mpi_second_cut 6 * 0bfd74660a2f6cedcf7d8256db4a63c996ffebbcdc2cf54397bfb72878c5a85a
mpi_second_cut 7 * (C) 1994-2005 Free Software Foundation, Inc.
mpi-genesis 8 *
mpi_second_cut 9 * This program is free software: you can redistribute it and/or modify
mpi-genesis 10 * it under the terms of the GNU General Public License as published by
mpi_second_cut 11 * the Free Software Foundation, either version 3 of the License, or
mpi-genesis 12 * (at your option) any later version.
mpi-genesis 13 *
mpi_second_cut 14 * This program is distributed in the hope that it will be useful,
mpi-genesis 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
mpi-genesis 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
mpi-genesis 17 * GNU General Public License for more details.
mpi-genesis 18 *
mpi-genesis 19 * You should have received a copy of the GNU General Public License
mpi_second_cut 20 * along with this program. If not, see <http://www.gnu.org/licenses/>.
mpi-genesis 21 */
mpi-genesis 22
mpi-genesis 23 #include <stdio.h>
mpi-genesis 24 #include <stdlib.h>
mpi_second_cut 25
mpi_second_cut 26 #include "knobs.h"
mpi-genesis 27 #include "mpi-internal.h"
mpi-genesis 28 #include "longlong.h"
mpi-genesis 29
mpi-genesis 30 mpi_limb_t
mpi-genesis 31 mpihelp_add_n( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
mpi-genesis 32 mpi_ptr_t s2_ptr, mpi_size_t size)
mpi-genesis 33 {
mpi-genesis 34 mpi_limb_t x, y, cy;
mpi-genesis 35 mpi_size_t j;
mpi-genesis 36
mpi-genesis 37 /* The loop counter and index J goes from -SIZE to -1. This way
mpi-genesis 38 the loop becomes faster. */
mpi-genesis 39 j = -size;
mpi-genesis 40
mpi-genesis 41 /* Offset the base pointers to compensate for the negative indices. */
mpi-genesis 42 s1_ptr -= j;
mpi-genesis 43 s2_ptr -= j;
mpi-genesis 44 res_ptr -= j;
mpi-genesis 45
mpi-genesis 46 cy = 0;
mpi-genesis 47 do {
mpi-genesis 48 y = s2_ptr[j];
mpi-genesis 49 x = s1_ptr[j];
mpi-genesis 50 y += cy; /* add previous carry to one addend */
mpi-genesis 51 cy = y < cy; /* get out carry from that addition */
mpi-genesis 52 y += x; /* add other addend */
mpi-genesis 53 cy += y < x; /* get out carry from that add, combine */
mpi-genesis 54 res_ptr[j] = y;
mpi-genesis 55 } while( ++j );
mpi-genesis 56
mpi-genesis 57 return cy;
mpi-genesis 58 }
mpi-genesis 59