#include "tommath_private.h"
#ifdef BN_MP_DECR_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.
*
* SPDX-License-Identifier: Unlicense
*/
/* Decrement "a" by one like "a--". Changes input! */
int mp_decr(mp_int *a)
{
int e = MP_OKAY;
if (IS_ZERO(a)) {
mp_set(a,1uL);
a->sign = MP_NEG;
return MP_OKAY;
} else if (a->sign == MP_NEG) {
a->sign = MP_ZPOS;
if ((e = mp_incr(a)) != MP_OKAY) {
return e;
}
/* There is no -0 in LTM */
if (!IS_ZERO(a)) {
a->sign = MP_NEG;
}
return MP_OKAY;
} else if (a->dp[0] > 1uL) {
a->dp[0]--;
if (a->dp[0] == 0) {
mp_zero(a);
}
return MP_OKAY;
}
return mp_sub_d(a, 1uL,a);
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
