Mercurial > dropbear
view libtommath/bn_mp_get_long.c @ 1626:9bd597d29590
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author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 14 Nov 2018 22:58:35 +0800 |
parents | 60fc6476e044 |
children | f52919ffd3b1 |
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#include <tommath_private.h> #ifdef BN_MP_GET_LONG_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://libtom.org */ /* get the lower unsigned long of an mp_int, platform dependent */ unsigned long mp_get_long(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); #if (ULONG_MAX != 0xffffffffuL) || (DIGIT_BIT < 32) while (--i >= 0) { res = (res << DIGIT_BIT) | DIGIT(a,i); } #endif return res; } #endif