Mercurial > dropbear
view bn_mp_get_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> |
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date | Wed, 08 Mar 2006 13:16:18 +0000 |
parents | |
children | 97db060d0ef5 |
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#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.org */ /* 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