kc3-lang/libtommath/bn_mp_decr.c

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• Hash : 4534056c
  Author :
  Date : 2019-05-13T00:22:18
  

  use enums mp_err, mp_ord, mp_bool, mp_sign * MP_USE_ENUMS enables enums * Wc++-compat catches some implicit conversions if MP_USE_ENUMS is defined * 100% backwards compatible API/ABI if MP_USE_ENUMS is not defined

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• bn_mp_decr.c

• #include "tommath_private.h"
  #ifdef BN_MP_DECR_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  /* Decrement "a" by one like "a--". Changes input! */
  mp_err mp_decr(mp_int *a)
  {
     mp_err e = MP_OKAY;
     if (MP_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 (!MP_IS_ZERO(a)) {
           a->sign = MP_NEG;
        }
        return MP_OKAY;
     } else if (a->dp[0] > 1uL) {
        a->dp[0]--;
        if (a->dp[0] == 0u) {
           mp_zero(a);
        }
        return MP_OKAY;
     } else {
        return mp_sub_d(a, 1uL,a);
     }
  }
  #endif
  

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