Function do_add

strings/decimal.c:1810–1888

}

static int do_add(const decimal_t *from1, const decimal_t *from2, decimal_t *to)
{
  int intg1=ROUND_UP(from1->intg), intg2=ROUND_UP(from2->intg),
      frac1=ROUND_UP(from1->frac), frac2=ROUND_UP(from2->frac),
      frac0= MY_MAX(frac1, frac2), intg0= MY_MAX(intg1, intg2), error;
  dec1 *buf1, *buf2, *buf0, *stop, *stop2, x, carry;

  sanity(to);

  /* is there a need for extra word because of carry ? */
  x=intg1 > intg2 ? from1->buf[0] :
    intg2 > intg1 ? from2->buf[0] :
    from1->buf[0] + from2->buf[0] ;
  if (unlikely(x > DIG_MAX-1)) /* yes, there is */
  {
    intg0++;
    to->buf[0]=0; /* safety */
  }

  FIX_INTG_FRAC_ERROR(to->len, intg0, frac0, error);
  if (unlikely(error == E_DEC_OVERFLOW))
  {
    max_decimal(to->len * DIG_PER_DEC1, 0, to);
    return error;
  }

  buf0=to->buf+intg0+frac0;

  to->sign=from1->sign;
  to->frac= MY_MAX(from1->frac, from2->frac);
  to->intg=intg0*DIG_PER_DEC1;
  if (unlikely(error))
  {
    set_if_smaller(to->frac, frac0*DIG_PER_DEC1);
    set_if_smaller(frac1, frac0);
    set_if_smaller(frac2, frac0);
    set_if_smaller(intg1, intg0);
    set_if_smaller(intg2, intg0);
  }

  /* part 1 - max(frac) ... min (frac) */
  if (frac1 > frac2)
  {
    buf1=from1->buf+intg1+frac1;
    stop=from1->buf+intg1+frac2;
    buf2=from2->buf+intg2+frac2;
    stop2=from1->buf+(intg1 > intg2 ? intg1-intg2 : 0);
  }
  else
  {
    buf1=from2->buf+intg2+frac2;
    stop=from2->buf+intg2+frac1;
    buf2=from1->buf+intg1+frac1;
    stop2=from2->buf+(intg2 > intg1 ? intg2-intg1 : 0);
  }
  while (buf1 > stop)
    *--buf0=*--buf1;