why add this code will got loop and compile running like stop

signal enableit : STD_LOGIC;
signal wholelooptrue : STD_LOGIC = '1';
enableit <= '1';
process(CLOCK_50)
    VARIABLE last_clk : std_logic := '0';
    VARIABLE counter : integer := 0;
    VARIABLE last_counter : integer := 0;
    
    begin
    while (whilelooptrue = enableit) loop
    
        if SW(0) = '1' then
            enableit <= '1';
            if (CLOCK_50 = '0') AND (last_clk = '1') then
                
                if (counter = 0) then
                    txdata8 <= preamble;
                end if;
                if (counter = 1) then
                    txdata8 <= preamble;
                end if;
                if (counter = 2) then
                    txdata8 <= preamble;
                end if;
                if (counter = 3) then
                    txdata8 <= preamble; --end
                end if;
                if (counter = 4) then
                    txdata8 <= preamble;
                end if;
                if (counter = 5) then
                    txdata8 <= preamble;
                end if;
                if (counter = 6) then
                    txdata8 <= preamble;
                end if;
                if (counter = 7) then
                    txdata8 <= SFD;
                end if;
                if (counter = 8) then
                    txdata8 <= dest_mac_addr1;
                end if;
                if (counter = 9) then
                    txdata8 <= dest_mac_addr2;
                end if;
                if (counter = 10) then
                    txdata8 <= dest_mac_addr3;
                end if;
                if (counter = 11) then
                    txdata8 <= dest_mac_addr4;
                end if;
                if (counter = 12) then
                    txdata8 <= dest_mac_addr5;
                end if;
                if (counter = 13) then
                    txdata8 <= dest_mac_addr6;
                end if;
                if (counter = 14) then
                    txdata8 <= src_mac_addr1;
                end if;
                if (counter = 15) then
                    txdata8 <= src_mac_addr2;
                end if;
                if (counter = 16) then
                    txdata8 <= src_mac_addr3;
                end if;
                if (counter = 17) then
                    txdata8 <= src_mac_addr4;
                end if;
                if (counter = 18) then
                    txdata8 <= src_mac_addr5;
                end if;
                if (counter = 19) then
                    txdata8 <= src_mac_addr6;
                end if;
                if (counter = 20) then
                    txdata8 <= wholepacketlength1;
                end if;            
                if (counter = 21) then
                    txdata8 <= wholepacketlength2;
                end if;            
                if (counter = 22) then
                    txdata8 <= payload;
                end if;            
                if (counter = 23) then
                    txdata8 <= emptyhex;
                end if;            
                if (counter = 24) then
                    txdata8 <= X"10";--CheckSumResult;
                end if;
                
                last_counter := counter;
                counter := counter + 1;
            end if;
            
            if (CLOCK_50 = '1') AND (last_clk = '0') then
                if (counter >= 25) then
                    enableit <= '0';
                end if;
            end if;
        else
            enableit <= '0';
        end if;
    end loop;
    last_clk := CLOCK_50;
    end process;