Mercurial > dropbear
diff libtommath/bn_mp_neg.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_neg.c Sat Jun 10 16:39:40 2006 +0000 @@ -0,0 +1,36 @@ +#include <tommath.h> +#ifdef BN_MP_NEG_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 + */ + +/* b = -a */ +int mp_neg (mp_int * a, mp_int * b) +{ + int res; + if (a != b) { + if ((res = mp_copy (a, b)) != MP_OKAY) { + return res; + } + } + + if (mp_iszero(b) != MP_YES) { + b->sign = (a->sign == MP_ZPOS) ? MP_NEG : MP_ZPOS; + } else { + b->sign = MP_ZPOS; + } + + return MP_OKAY; +} +#endif