Mercurial > dropbear
diff libtommath/bn_mp_get_int.c @ 389:5ff8218bcee9
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e)
to branch 'au.asn.ucc.matt.dropbear' (head ecd779509ef23a8cdf64888904fc9b31d78aa933)
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Thu, 11 Jan 2007 03:14:55 +0000 |
parents | eed26cff980b |
children | 60fc6476e044 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtommath/bn_mp_get_int.c Thu Jan 11 03:14:55 2007 +0000 @@ -0,0 +1,45 @@ +#include <tommath.h> +#ifdef BN_MP_GET_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.com + */ + +/* 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; +} +#endif + +/* $Source: /cvs/libtom/libtommath/bn_mp_get_int.c,v $ */ +/* $Revision: 1.3 $ */ +/* $Date: 2006/03/31 14:18:44 $ */