Mercurial > dropbear
diff libtommath/bn_mp_set_int.c @ 330:5488db2e9e4e
merge of 332f709a4cb39cde4cedab7c3be89e05f3023067
and ca4ca78b82c5d430c69ce01bf794e8886ce81431
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Sat, 10 Jun 2006 16:39:40 +0000 |
parents | eed26cff980b |
children | 5ff8218bcee9 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_mp_set_int.c Sat Jun 10 16:39:40 2006 +0000 @@ -0,0 +1,44 @@ +#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, [email protected], http://math.libtomcrypt.org + */ + +/* 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