diff options
Diffstat (limited to 'libtommath/bn_mp_set_int.c')
-rw-r--r-- | libtommath/bn_mp_set_int.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/libtommath/bn_mp_set_int.c b/libtommath/bn_mp_set_int.c new file mode 100644 index 0000000..35e844f --- /dev/null +++ b/libtommath/bn_mp_set_int.c @@ -0,0 +1,48 @@ +#include <tommath.h> +#ifdef BN_MP_SET_INT_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@gmail.com, http://math.libtomcrypt.com + */ + +/* set a 32-bit const */ +int mp_set_int (mp_int * a, unsigned long b) +{ + int x, res; + + mp_zero (a); + + /* set four bits at a time */ + for (x = 0; x < 8; x++) { + /* shift the number up four bits */ + if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) { + return res; + } + + /* OR in the top four bits of the source */ + a->dp[0] |= (b >> 28) & 15; + + /* shift the source up to the next four bits */ + b <<= 4; + + /* ensure that digits are not clamped off */ + a->used += 1; + } + mp_clamp (a); + return MP_OKAY; +} +#endif + +/* $Source: /cvs/libtom/libtommath/bn_mp_set_int.c,v $ */ +/* $Revision: 1.3 $ */ +/* $Date: 2006/03/31 14:18:44 $ */ |