1f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#include <tommath.h> 2f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_MP_MUL_D_C 3f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* LibTomMath, multiple-precision integer library -- Tom St Denis 4f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 5f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * LibTomMath is a library that provides multiple-precision 6f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * integer arithmetic as well as number theoretic functionality. 7f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 8f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The library was designed directly after the MPI library by 9f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Michael Fromberger but has been written from scratch with 10f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * additional optimizations in place. 11f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 12f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The library is free for all purposes without any express 13f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * guarantee it works. 14f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 15f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com 16f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project */ 17f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 18f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* multiply by a digit */ 19f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint 20f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectmp_mul_d (mp_int * a, mp_digit b, mp_int * c) 21f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{ 22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project mp_digit u, *tmpa, *tmpc; 23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project mp_word r; 24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int ix, res, olduse; 25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* make sure c is big enough to hold a*b */ 27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (c->alloc < a->used + 1) { 28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((res = mp_grow (c, a->used + 1)) != MP_OKAY) { 29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return res; 30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* get the original destinations used count */ 34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project olduse = c->used; 35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* set the sign */ 37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project c->sign = a->sign; 38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* alias for a->dp [source] */ 40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project tmpa = a->dp; 41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* alias for c->dp [dest] */ 43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project tmpc = c->dp; 44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* zero carry */ 46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project u = 0; 47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* compute columns */ 49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project for (ix = 0; ix < a->used; ix++) { 50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* compute product and carry sum for this term */ 51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project r = ((mp_word) u) + ((mp_word)*tmpa++) * ((mp_word)b); 52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* mask off higher bits to get a single digit */ 54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *tmpc++ = (mp_digit) (r & ((mp_word) MP_MASK)); 55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* send carry into next iteration */ 57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project u = (mp_digit) (r >> ((mp_word) DIGIT_BIT)); 58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* store final carry [if any] and increment ix offset */ 61f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *tmpc++ = u; 62f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project ++ix; 63f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 64f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* now zero digits above the top */ 65f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project while (ix++ < olduse) { 66f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project *tmpc++ = 0; 67f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 68f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 69f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* set used count */ 70f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project c->used = a->used + 1; 71f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project mp_clamp(c); 72f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 73f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return MP_OKAY; 74f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project} 75f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 76f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 77f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtommath/bn_mp_mul_d.c,v $ */ 78f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.3 $ */ 79f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/03/31 14:18:44 $ */ 80