1f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#include <tommath.h> 2f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_MP_MUL_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/* high level multiplication (handles sign) */ 19f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Projectint mp_mul (mp_int * a, mp_int * b, mp_int * c) 20f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project{ 21f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int res, neg; 22f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project neg = (a->sign == b->sign) ? MP_ZPOS : MP_NEG; 23f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 24f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* use Toom-Cook? */ 25f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_MP_TOOM_MUL_C 26f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (MIN (a->used, b->used) >= TOOM_MUL_CUTOFF) { 27f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project res = mp_toom_mul(a, b, c); 28f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } else 29f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 30f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_MP_KARATSUBA_MUL_C 31f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* use Karatsuba? */ 32f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if (MIN (a->used, b->used) >= KARATSUBA_MUL_CUTOFF) { 33f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project res = mp_karatsuba_mul (a, b, c); 34f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } else 35f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 36f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project { 37f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project /* can we use the fast multiplier? 38f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * 39f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * The fast multiplier can be used if the output will 40f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * have less than MP_WARRAY digits and the number of 41f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project * digits won't affect carry propagation 42f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project */ 43f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project int digs = a->used + b->used + 1; 44f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 45f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_FAST_S_MP_MUL_DIGS_C 46f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project if ((digs < MP_WARRAY) && 47f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project MIN(a->used, b->used) <= 48f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project (1 << ((CHAR_BIT * sizeof (mp_word)) - (2 * DIGIT_BIT)))) { 49f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project res = fast_s_mp_mul_digs (a, b, c, digs); 50f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } else 51f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 52f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#ifdef BN_S_MP_MUL_DIGS_C 53f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project res = s_mp_mul (a, b, c); /* uses s_mp_mul_digs */ 54f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#else 55f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project res = MP_VAL; 56f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 57f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 58f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project } 59f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project c->sign = (c->used > 0) ? neg : MP_ZPOS; 60f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project return res; 61f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project} 62f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project#endif 63f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project 64f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Source: /cvs/libtom/libtommath/bn_mp_mul.c,v $ */ 65f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Revision: 1.3 $ */ 66f7fc46c63fdc8f39234fea409b8dbe116d73ebf8The Android Open Source Project/* $Date: 2006/03/31 14:18:44 $ */ 67