control_unit.vhd

Library IEEE;
USE IEEE.std_logic_1164.all;
entity control_unit is
port (
-- INPUTS 
IR : in std_logic_vector (31 downto 0);

-- OUTPUTS (CONTROL SIGNALS):
OUT_SIG : out std_logic ;
IN_SIG  : out std_logic ;
ALU_OPR : out std_logic_vector (3 downto 0);
ALU_SRC : out std_logic ;
REG_DST : out std_logic ;
MEM_TO_REG : out std_logic ;
FETCH_EN : out std_logic ;
DATA_EN : out std_logic ;
ALU_EN :  out std_logic ;
BR_EN :  out std_logic ;
MEM_WR_EN :  out std_logic ;
MEM_RD_EN : out std_logic ;
SWAP : out std_logic ;
IN_SP  :  out std_logic ;
SP_INC_DEC : out std_logic ;
EA_IMM_SEL : out std_logic ;
JMP : out std_logic ;
JZ : out std_logic ;
FUNC : out std_logic ;
RTI : out std_logic ;
WB : out std_logic ;
FLUSH_JMP : out std_logic ;
FLUSH_FUNC : out std_logic ;
FLUSH_JZ  : out std_logic 
);
end entity;

architecture control_unit_arch of control_unit is
begin
process(IR)
begin
    case IR(31 downto 27) is
        -- ONE OPERAND
        --
        -- OPERATION : NOP
        when "00000" =>
            -- OPERATION : NOP
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';        
        --
        -- OPERATION : NOT
        when "00001" =>
            -- OPERATION : NOT
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --            
        -- OPERATION : INC
        when "00010" =>
            -- OPERATION : INC
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0001";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : DEC
        when "00011" =>
            -- OPERATION : DEC
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0010";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : OUT
        when "00100" =>
            -- OPERATION : OUT
            OUT_SIG         <= '1';
            IN_SIG          <= '0';
            ALU_OPR         <= "1000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --  
        -- OPERATION : IN
        when "00101" =>
            -- OPERATION : IN
            OUT_SIG         <= '0';
            IN_SIG          <= '1';
            ALU_OPR         <= "1001";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        
        --------------------------------------
        -- TWO OPERANDS
        --
        -- OPERATION : SWAP
        when "01000" =>
            -- OPERATION : SWAP NEED MODIFICATION
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1000";
            ALU_SRC         <= '0'; --
            REG_DST         <= '0'; --
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '1';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0'; --
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : ADD
        when "01001" =>
            -- OPERATION : ADD
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0011";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : IADD -- COPIED JUST LIKE ADD NEED MODIFICATION
        when "01010" =>
            -- OPERATION : IADD -- COPIED JUST LIKE ADD NEED MODIFICATION
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0011";
            ALU_SRC         <= '1';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : SUB
        when "01011" =>
            -- OPERATION : SUB
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0100";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : AND 
        when "01100" =>
            -- OPERATION : AND 
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0101";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0'; --
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        --
        -- OPERATION : OR 
        when "01101" =>
            -- OPERATION : OR 
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0110";
            ALU_SRC         <= '0';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        --
        -- OPERATION : SHL
        when "01110" =>
            -- OPERATION : SHL
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1010";
            ALU_SRC         <= '1';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : SHR
        when "01111" =>
            -- OPERATION : SHR
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1011";
            ALU_SRC         <= '1';
            REG_DST         <= '1';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        
        -- 
        
        -- MEMEORY INSTRUCTIONS
        -- OPERATION : PUSH
        when "10000" =>
            -- OPERATION : PUSH
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0';
            BR_EN           <= '0';
            MEM_WR_EN       <= '1';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '1';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : POP
        when "10001" =>
            -- OPERATION : POP
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '1';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '0';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '1';
            SWAP            <= '0';
            IN_SP           <= '1';
            SP_INC_DEC      <= '1';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        --
        -- OPERATION : LDM 
        when "10010" =>
            -- OPERATION : LDM
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1001";
            ALU_SRC         <= '1';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '1';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        --
        -- OPERATION : LDD 
        when "10011" =>
            -- OPERATION : LDD
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1001";
            ALU_SRC         <= '1';
            REG_DST         <= '0';
            MEM_TO_REG      <= '1';
            FETCH_EN        <= '0';
            DATA_EN         <= '1';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '1';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '1';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        --
        -- OPERATION : STD 
        when "10100" =>
            -- OPERATION : STD
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1001";
            ALU_SRC         <= '1';
            REG_DST         <= '0'; --X
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0'; -- modified as alu.txt file
            BR_EN           <= '0';
            MEM_WR_EN       <= '1';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '1';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';

        --

        -- BRANCH INSTRUCTIONS
        --
        -- OPERATION : JZ  -- MODIFIY
        when "11000" =>
            -- OPERATION : JZ 
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0111";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '1';
            BR_EN           <= '1';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0'; -- MODIFIY
            JMP             <= '0';
            JZ              <= '1';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '1';
        --
        -- OPERATION : JMP 
        when "11001" =>
            -- OPERATION : JMP
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0';
            BR_EN           <= '1';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '1';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '1';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : CALL 
        when "11010" =>
            -- OPERATION : CALL -- MODIFIY
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "1001";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '1';
            BR_EN           <= '0';
            MEM_WR_EN       <= '1';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '1';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '1';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '1';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : RET 
        when "11011" =>
            -- OPERATION : RET
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '1';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '1';
            SWAP            <= '0';
            IN_SP           <= '1';
            SP_INC_DEC      <= '1';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '1';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '1';
            FLUSH_JZ        <= '0';
        --
        -- OPERATION : RTI 
        when "11100" =>
            -- OPERATION : RTI
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '1';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '1';
            SWAP            <= '0';
            IN_SP           <= '1';
            SP_INC_DEC      <= '1';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '1';
            RTI             <= '1';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '1';
            FLUSH_JZ        <= '0';
        --
        when others =>
            OUT_SIG         <= '0';
            IN_SIG          <= '0';
            ALU_OPR         <= "0000";
            ALU_SRC         <= '0';
            REG_DST         <= '0';
            MEM_TO_REG      <= '0';
            FETCH_EN        <= '0';
            DATA_EN         <= '0';
            ALU_EN          <= '0';
            BR_EN           <= '0';
            MEM_WR_EN       <= '0';
            MEM_RD_EN       <= '0';
            SWAP            <= '0';
            IN_SP           <= '0';
            SP_INC_DEC      <= '0';
            EA_IMM_SEL      <= '0';
            JMP             <= '0';
            JZ              <= '0';
            FUNC            <= '0';
            RTI             <= '0';
            WB              <= '0';
            FLUSH_JMP       <= '0';
            FLUSH_FUNC      <= '0';
            FLUSH_JZ        <= '0';       
    end case;
end process;
end architecture;