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ch1_mpi                 1 /* mpihelp-mul_3.c  -  MPI helper functions
ch1_mpi 2 * Modified by No Such Labs. (C) 2015. See README.
ch1_mpi 3 *
ch1_mpi 4 * This file was originally part of Gnu Privacy Guard (GPG), ver. 1.4.10,
ch1_mpi 5 * SHA256(gnupg-1.4.10.tar.gz):
ch1_mpi 6 * 0bfd74660a2f6cedcf7d8256db4a63c996ffebbcdc2cf54397bfb72878c5a85a
ch1_mpi 7 * (C) 1994-2005 Free Software Foundation, Inc.
ch1_mpi 8 *
ch1_mpi 9 * This program is free software: you can redistribute it and/or modify
ch1_mpi 10 * it under the terms of the GNU General Public License as published by
ch1_mpi 11 * the Free Software Foundation, either version 3 of the License, or
ch1_mpi 12 * (at your option) any later version.
ch1_mpi 13 *
ch1_mpi 14 * This program is distributed in the hope that it will be useful,
ch1_mpi 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
ch1_mpi 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
ch1_mpi 17 * GNU General Public License for more details.
ch1_mpi 18 *
ch1_mpi 19 * You should have received a copy of the GNU General Public License
ch1_mpi 20 * along with this program. If not, see <http://www.gnu.org/licenses/>.
ch1_mpi 21 */
ch1_mpi 22
ch1_mpi 23 #include <stdio.h>
ch1_mpi 24 #include <stdlib.h>
ch1_mpi 25
ch1_mpi 26 #include "knobs.h"
ch1_mpi 27 #include "mpi-internal.h"
ch1_mpi 28 #include "longlong.h"
ch1_mpi 29
ch1_mpi 30
ch1_mpi 31 mpi_limb_t
ch1_mpi 32 mpihelp_submul_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
ch1_mpi 33 mpi_size_t s1_size, mpi_limb_t s2_limb)
ch1_mpi 34 {
ch1_mpi 35 mpi_limb_t cy_limb;
ch1_mpi 36 mpi_size_t j;
ch1_mpi 37 mpi_limb_t prod_high, prod_low;
ch1_mpi 38 mpi_limb_t x;
ch1_mpi 39
ch1_mpi 40 /* The loop counter and index J goes from -SIZE to -1. This way
ch1_mpi 41 * the loop becomes faster. */
ch1_mpi 42 j = -s1_size;
ch1_mpi 43 res_ptr -= j;
ch1_mpi 44 s1_ptr -= j;
ch1_mpi 45
ch1_mpi 46 cy_limb = 0;
ch1_mpi 47 do {
ch1_mpi 48 umul_ppmm( prod_high, prod_low, s1_ptr[j], s2_limb);
ch1_mpi 49
ch1_mpi 50 prod_low += cy_limb;
ch1_mpi 51 cy_limb = (prod_low < cy_limb?1:0) + prod_high;
ch1_mpi 52
ch1_mpi 53 x = res_ptr[j];
ch1_mpi 54 prod_low = x - prod_low;
ch1_mpi 55 cy_limb += prod_low > x?1:0;
ch1_mpi 56 res_ptr[j] = prod_low;
ch1_mpi 57 } while( ++j );
ch1_mpi 58
ch1_mpi 59 return cy_limb;
ch1_mpi 60 }
ch1_mpi 61
ch1_mpi 62