function ModuloReal takes real dividend, real divisor returns real
       local real modulus = dividend - I2R(R2I(dividend / divisor)) * divisor
       // If the dividend was negative, the above modulus calculation will
       // be negative, but within (-divisor..0).  We can add (divisor) to
       // shift this result into the desired range of (0..divisor).
       if (modulus < 0) then
           set modulus = modulus + divisor
       return modulus

Gets the remainder of dividend divided by divisor as a real.