usage of arithmetic megafunctions

since i'm a beginner, i dont know the best way of using FP MF's. after calculation completed by MF, i need a ready signal to start the next MF calculation process. i want to know the most suitable method? is my code below suitable? and could you please warn me of what is wrong?

process (reset,clock,t)

variable clk_u:integer:=0;

variable clk_end:integer:=0;

variable state,state_next:integer:=0;

variable rdy:std_logic:='0';

begin

if reset='1' then

aclr<='1';

clk_en_mul<='0';

rdy:='0';

state:=0;

else

if rdy='0' and rising_edge(clock) then

case state is

when 0=>

aclr<='0';

clk_en_mul<='0';

state_next:=1;

clk_end:=2;

when 1=>

dataa_mul<=x"3A4DE32E";

datab_mul<=x"40000000";

state_next:=2;

clk_end:=2;

when 2=>

clk_en_mul<='1';

state_next:=3;

clk_end:=11;

when 3=>

clk_en_mul<='0';

state_next:=4;

clk_end:=1;

when 4=>

clk_en_mul<='0';

result<=result_mul;

rdy:='1';

state_next:=5;

clk_end:=2;

when others=>

null;

end case;

clk_u:=clk_u+1;

if clk_u>clk_end then

state:=state_next;

clk_u:=0;

end if;

end if;

end if;

ready<=rdy;

end process;

Regards

Bedri