Mercurial > dropbear
comparison bn_mp_set_int.c @ 282:91fbc376f010 libtommath-orig libtommath-0.35
Import of libtommath 0.35
From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Wed, 08 Mar 2006 13:16:18 +0000 |
| parents | |
| children | 97db060d0ef5 |
comparison
equal
deleted
inserted
replaced
| -1:000000000000 | 282:91fbc376f010 |
|---|---|
| 1 #include <tommath.h> | |
| 2 #ifdef BN_MP_SET_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, [email protected], http://math.libtomcrypt.org | |
| 16 */ | |
| 17 | |
| 18 /* set a 32-bit const */ | |
| 19 int mp_set_int (mp_int * a, unsigned long b) | |
| 20 { | |
| 21 int x, res; | |
| 22 | |
| 23 mp_zero (a); | |
| 24 | |
| 25 /* set four bits at a time */ | |
| 26 for (x = 0; x < 8; x++) { | |
| 27 /* shift the number up four bits */ | |
| 28 if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) { | |
| 29 return res; | |
| 30 } | |
| 31 | |
| 32 /* OR in the top four bits of the source */ | |
| 33 a->dp[0] |= (b >> 28) & 15; | |
| 34 | |
| 35 /* shift the source up to the next four bits */ | |
| 36 b <<= 4; | |
| 37 | |
| 38 /* ensure that digits are not clamped off */ | |
| 39 a->used += 1; | |
| 40 } | |
| 41 mp_clamp (a); | |
| 42 return MP_OKAY; | |
| 43 } | |
| 44 #endif |