| #include <tommath.h> |
| #ifdef BN_MP_REDUCE_2K_SETUP_L_C |
| /* 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 |
| */ |
| |
| /* determines the setup value */ |
| int mp_reduce_2k_setup_l(mp_int *a, mp_int *d) |
| { |
| int res; |
| mp_int tmp; |
| |
| if ((res = mp_init(&tmp)) != MP_OKAY) { |
| return res; |
| } |
| |
| if ((res = mp_2expt(&tmp, mp_count_bits(a))) != MP_OKAY) { |
| goto ERR; |
| } |
| |
| if ((res = s_mp_sub(&tmp, a, d)) != MP_OKAY) { |
| goto ERR; |
| } |
| |
| ERR: |
| mp_clear(&tmp); |
| return res; |
| } |
| #endif |