ERROR:Xst:528 - Multi-source in Unit <diviseur> on signal <endOfCalculations>; this signal is connected to multiple drivers.

dataPath:process(clk,reset)
begin
if reset='1' then quotient<=(others=>'0');
                        rest<=(others=>'0');
                        operand<=(others=>'0');
                        fin<='0';
else
    if rising_edge(clk) then
       if loadDivisorInReg='1' then divisor<=load; end if;
        if loadDividenedInReg='1' then dividened<=load; end if;
        if initializeOperand='1' then operand<="0000000"&dividened(7);end       if;
        if runResult='1' then substractionResult<=operand-divisor;end if;
        if runQuotient='1' then quotient<=quotient(6 downto 0)&(not(substractionResult(7)));end if;
        if runOperand='1' then
                        if substractionResult(7)='1' then
                                        operand<=operand(6 downto 0) &dividened(7);
                                        dividened<=dividened(6 downto 0) &'0';
                        else
                                operand<=substractionResult(6 downto 0) &'0';
                       end if;
                        if count="111" then count<=(others=>'0');endOfDivisionFlag<='1';
                       else count <= count+1; endOfDivisionFlag<='0';
                        end if;
        end if;
        if (endOfCalculations='1') then rest<=operand;end if;
    end if;
end if;
end process dataPath;

-- control signals
-- loading divisor
loadDivisorInReg<= '1' when state=E0 else '0';
-- loading dividened
loadDividenedInReg<= '1' when state=E1 else '0';
-- initializing the operand
initializeOperand <= '1' when state=E3 else '0';
-- run substraction result
runResult<= '1' when state=E4 else '0';
-- run quotient
runQuotient<= '1' when state=E5 else '0';
-- find operand
runOperand<= '1' when state=E6 else '0';
-- end of division
endOfCalculations<='1' when (state=E7) else '0';