1 #include <tommath.h> 2 #ifdef BN_MP_GET_INT_C 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis 4 * 5 * LibTomMath is a library that provides multiple-precision 6 * integer arithmetic as well as number theoretic functionality. 7 * 8 * The library was designed directly after the MPI library by 9 * Michael Fromberger but has been written from scratch with 10 * additional optimizations in place. 11 * 12 * The library is free for all purposes without any express 13 * guarantee it works. 14 * 15 * Tom St Denis, tomstdenis (at) gmail.com, http://math.libtomcrypt.com 16 */ 17 18 /* get the lower 32-bits of an mp_int */ 19 unsigned long mp_get_int(mp_int * a) 20 { 21 int i; 22 unsigned long res; 23 24 if (a->used == 0) { 25 return 0; 26 } 27 28 /* get number of digits of the lsb we have to read */ 29 i = MIN(a->used,(int)((sizeof(unsigned long)*CHAR_BIT+DIGIT_BIT-1)/DIGIT_BIT))-1; 30 31 /* get most significant digit of result */ 32 res = DIGIT(a,i); 33 34 while (--i >= 0) { 35 res = (res << DIGIT_BIT) | DIGIT(a,i); 36 } 37 38 /* force result to 32-bits always so it is consistent on non 32-bit platforms */ 39 return res & 0xFFFFFFFFUL; 40 } 41 #endif 42 43 /* $Source: /cvs/libtom/libtommath/bn_mp_get_int.c,v $ */ 44 /* $Revision: 1.3 $ */ 45 /* $Date: 2006/03/31 14:18:44 $ */ 46
