tommath/bn_mp_neg.c

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#include <tommath.h>
#ifdef BN_MP_NEG_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
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* LibTomMath is a library that provides multiple-precision
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* integer arithmetic as well as number theoretic functionality.
*
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* The library was designed directly after the MPI library by
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* 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.
*
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* Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
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*/
/* b = -a */
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int mp_neg (mp_int * a, mp_int * b)
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{
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int res;
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if (a != b) {
if ((res = mp_copy (a, b)) != MP_OKAY) {
return res;
}
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}
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if (mp_iszero(b) != MP_YES) {
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b->sign = (a->sign == MP_ZPOS) ? MP_NEG : MP_ZPOS;
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} else {
b->sign = MP_ZPOS;
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}
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return MP_OKAY;
}
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#endif
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/* $Source$ */
/* $Revision$ */
/* $Date$ */