| /* LibTomMath, multiple-precision integer library -- Tom St Denis |
| * |
| * LibTomMath is a library that provides multiple-precision |
| * integer arithmetic as well as number theoretic functionality. |
| * |
| * The library was designed directly after the MPI library by |
| * Michael Fromberger but has been written from scratch with |
| * additional optimizations in place. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org |
| */ |
| #include <tommath.h> |
| |
| /* get the lower 32-bits of an mp_int */ |
| unsigned long mp_get_int(mp_int * a) |
| { |
| int i; |
| unsigned long res; |
| |
| if (a->used == 0) { |
| return 0; |
| } |
| |
| /* get number of digits of the lsb we have to read */ |
| i = MIN(a->used,(int)((sizeof(unsigned long)*CHAR_BIT+DIGIT_BIT-1)/DIGIT_BIT))-1; |
| |
| /* get most significant digit of result */ |
| res = DIGIT(a,i); |
| |
| while (--i >= 0) { |
| res = (res << DIGIT_BIT) | DIGIT(a,i); |
| } |
| |
| /* force result to 32-bits always so it is consistent on non 32-bit platforms */ |
| return res & 0xFFFFFFFFUL; |
| } |