sarjumaharaj
Junior Member level 1
Hello, I am designing the controller for booth multiplier. (more info on will be found : BOOTH MULTIPLIER ). You can see the ASM CHART ON THE LINK. However, i've added a few more states like hold and end to it. But leaving the design aside, can anyone please see what is wrong with the code. It shows error near when in multiple number of lines. For now I don't need help with design of the controller just the code syntax. Been stuck here for hours. Please anyone!! thanks.
And I am very new to this group, so I don't know the ins and outs of the group properly so if I'm violating any rule please do tell me. I will positively take your comments and criticism.
And I am very new to this group, so I don't know the ins and outs of the group properly so if I'm violating any rule please do tell me. I will positively take your comments and criticism.
Code:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity booth_controller is
port (clk , qn , qnprev, count : in std_logic;
load , start, count_en, clr, rshift, add1 ,sub : out std_logic --is START in std_logic or out
);
end booth_controller;
architecture Behavioral of booth_controller is
type state_type is (init, hold, subt, addi, shift, counter, done);
signal sreg, snext : state_type;
begin
process (clk)
begin
if rising_edge (clk) then
sreg <= snext ;
end if ;
end process;
process (sreg)
begin
case sreg is
when init =>
-- here the start state hasn't been defined
clr <= '0' ;
if (start <= '1' )then
snext <= hold;
else
snext <= init;
end if;
when hold => start<='0';
if(load <= '1' and qn <= '1' and qnprev <='0' ) then
snext <= sub ;
else if (load <= '1' and qn <= '1' and qnprev <= '1' ) or (load <='1' and qn <='0' and qnprev <= '0' ) then
snext <= shift ;
else if (load <= '1' and qn <= '0' and qnprev <='1' ) then
snext <= add ;
elsif (load<= '0' ) then
snext <= hold;
end if ;
when subt=> sub <= '1' ;
snext <=shift;
when addi => add1 <= '1';
snext <= shift ;
when shift => add1 <= '0';
sub <= '0';
if (count != '0') then
snext <= hold;
else
snext <= done;
end if ;
when done => if (start <= '1') then
snext <= init ;
else
snext <= done;
end if ;
when others => snext <= init;
end case ;
end process ;
end Behavioral;