kc3-lang/libtommath/bn_mp_add.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_add.c

• #include "tommath_private.h"
  #ifdef BN_MP_ADD_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  /* high level addition (handles signs) */
  mp_err mp_add(const mp_int *a, const mp_int *b, mp_int *c)
  {
     mp_sign sa, sb;
     mp_err 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
  

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