## Mercurial > dropbear

### view libtommath/bn_mp_add.c @ 457:e430a26064ee DROPBEAR_0.50

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Make dropbearkey only generate 1024 bit keys

author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Aug 2007 15:57:50 +0000 |

parents | 5ff8218bcee9 |

children | 60fc6476e044 |

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#include <tommath.h> #ifdef BN_MP_ADD_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 */ /* high level addition (handles signs) */ int mp_add (mp_int * a, mp_int * b, mp_int * c) { int sa, sb, res; /* get sign of both inputs */ sa = a->sign; sb = b->sign; /* handle two cases, not four */ if (sa == sb) { /* both positive or both negative */ /* add their magnitudes, copy the sign */ c->sign = sa; res = s_mp_add (a, b, c); } else { /* one positive, the other negative */ /* subtract the one with the greater magnitude from */ /* the one of the lesser magnitude. The result gets */ /* the sign of the one with the greater magnitude. */ if (mp_cmp_mag (a, b) == MP_LT) { c->sign = sb; res = s_mp_sub (b, a, c); } else { c->sign = sa; res = s_mp_sub (a, b, c); } } return res; } #endif /* $Source: /cvs/libtom/libtommath/bn_mp_add.c,v $ */ /* $Revision: 1.3 $ */ /* $Date: 2006/03/31 14:18:44 $ */