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      return(precision);
  } while (--precision);
  return(precision);
}

void CRSALib::unitfill0(unitptr r,word16 unitcount)
{
  while (unitcount--) *r++ = 0;
}

int CRSALib::mp_udiv(register unitptr remainder,register unitptr quotient,
  register unitptr dividend,register unitptr divisor)
{
  int bits;
  short dprec;
  register unit bitmask;
  if (( ((*(divisor))==(0)) && (significance(divisor)<=1) ))
    return(-1);

  mp_init(remainder,0);
  mp_init(quotient,0);

  {
    dprec = significance(dividend);
    if (!dprec) return(0);
    bits = ((dprec) << 4);
    (dividend) = ((dividend)+(dprec)-1);
    bitmask = ((unit) 0x8000);
    while (!(*(dividend) & bitmask))
    {
      bitmask >>= 1;
      bits--;
    }
  };

  (quotient) = ((quotient)+(dprec)-1);

  while (bits--)
  {
    mp_rotate_left(remainder,(boolean)((*(dividend) & bitmask)!=0));
    if (mp_compare(remainder,divisor) >= 0)
    {
      mp_subb(remainder,divisor,(boolean)0);
      *(quotient) |= bitmask;
    }
    {
      if (!(bitmask >>= 1))
      {
        bitmask = ((unit) 0x8000);
        ((dividend)--); ((quotient)--);
      }
    };
  }
  return(0);
}


int CRSALib::mp_div(register unitptr remainder,register unitptr quotient,
  register unitptr dividend,register unitptr divisor)
{
  boolean dvdsign,dsign;
  int status;
  dvdsign = (((signedunit) (*((dividend)+(global_precision)-1)) < 0)!=0);
  dsign = (((signedunit) (*((divisor)+(global_precision)-1)) < 0)!=0);
  if (dvdsign) mp_neg(dividend);
  if (dsign) mp_neg(divisor);
  status = mp_udiv(remainder,quotient,dividend,divisor);
  if (dvdsign) mp_neg(dividend);
  if (dsign) mp_neg(divisor);
  if (status<0) return(status);
  if (dvdsign) mp_neg(remainder);
  if (dvdsign ^ dsign) mp_neg(quotient);
  return(status);
}


word16 CRSALib::mp_shortdiv(register unitptr quotient,
  register unitptr dividend,register word16 divisor)
{
  int bits;
  short dprec;
  register unit bitmask;
  register word16 remainder;
  if (!divisor)
    return(-1);
  remainder=0;
  mp_init(quotient,0);

  {
    dprec = significance(dividend);
    if (!dprec) return(0);
    bits = ((dprec) << 4);
    (dividend) = ((dividend)+(dprec)-1);
    bitmask = ((unit) 0x8000);
    while (!(*(dividend) & bitmask))
    {
      bitmask >>= 1;
      bits--;
    }
  };

  (quotient) = ((quotient)+(dprec)-1);

  while (bits--)
  {
    remainder <<= 1;
    if ((*(dividend) & bitmask))
      remainder++;
    if (remainder >= divisor)
    {
      remainder -= divisor;
      *(quotient) |= bitmask;
    }
    {
      if (!(bitmask >>= 1))
      {
        bitmask = ((unit) 0x8000);
        ((dividend)--);
        ((quotient)--);
      }
    };
  }
  return(remainder);
}


int CRSALib::mp_mod(register unitptr remainder,
  register unitptr dividend,register unitptr divisor)
{
  int bits;
  short dprec;
  register unit bitmask;