----------------------------------------------------------------------------------
-- Company: 
-- Engineer: 
-- 
-- Create Date: 15.05.2023 14:29:58
-- Design Name: 
-- Module Name: Pipeline - Behavioral
-- Project Name: 
-- Target Devices: 
-- Tool Versions: 
-- Description: 
-- 
-- Dependencies: 
-- 
-- Revision:
-- Revision 0.01 - File Created
-- Additional Comments:
-- 
----------------------------------------------------------------------------------


library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
--use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating
-- any Xilinx leaf cells in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity Pipeline is
    Port ( Clk : in STD_LOGIC);
end Pipeline;

architecture Behavioral of Pipeline is

    component IP is
    port ( CLK : in STD_LOGIC;
           RST : in STD_LOGIC; -- rst when 0
           LOAD : in STD_LOGIC;
           EN : in STD_LOGIC; -- enable when 1
           Din : in STD_LOGIC_VECTOR (7 downto 0);
           Dout : out STD_LOGIC_VECTOR (7 downto 0));
    end component;

    signal IP_out : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    signal Rst : STD_LOGIC; -- to modify  
    
    component InstructionMemory
    Port ( Addr : in STD_LOGIC_VECTOR (7 downto 0);
           Clk : in STD_LOGIC;
           Inst_out : out STD_LOGIC_VECTOR (31 downto 0));
    end component;
    
    signal Li : STD_LOGIC_VECTOR (31 downto 0) := (others => '0');
    
    component Stage_Li_Di
    Port ( In_A : in STD_LOGIC_VECTOR (7 downto 0);
           In_B : in STD_LOGIC_VECTOR (7 downto 0);
           In_C : in STD_LOGIC_VECTOR (7 downto 0);
           In_Op : in STD_LOGIC_VECTOR (7 downto 0);
           Clk : in STD_LOGIC;
           Out_A : out STD_LOGIC_VECTOR (7 downto 0);
           Out_B : out STD_LOGIC_VECTOR (7 downto 0);
           Out_Op : out STD_LOGIC_VECTOR (7 downto 0);
           Out_C : out STD_LOGIC_VECTOR (7 downto 0)
        );
    end component;
    
    signal Li_A, Li_Op, Li_B, Li_C : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    
    component Registers
    Port ( Addr_A : in STD_LOGIC_VECTOR (3 downto 0);
           Addr_B : in STD_LOGIC_VECTOR (3 downto 0);
           Addr_W : in STD_LOGIC_VECTOR (3 downto 0);
           W : in STD_LOGIC;
           Data : in STD_LOGIC_VECTOR (7 downto 0);
           Rst : in STD_LOGIC;
           Clk : in STD_LOGIC;
           QA : out STD_LOGIC_VECTOR (7 downto 0);
           QB : out STD_LOGIC_VECTOR (7 downto 0)
        );
    end component;
    
    signal Di_A, Di_Op, Di_B, Di_C : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    signal Di_RegB, Di_FinalB, Di_C2 : STD_LOGIC_VECTOR (7 downto 0) := (others => '0'); 
    
    component Stage_Di_Ex
    Port ( In_A : in STD_LOGIC_VECTOR (7 downto 0);
           In_B : in STD_LOGIC_VECTOR (7 downto 0);
           In_C : in STD_LOGIC_VECTOR (7 downto 0);
           In_Op : in STD_LOGIC_VECTOR (7 downto 0);
           Clk : in STD_LOGIC;
           Out_A : out STD_LOGIC_VECTOR (7 downto 0);
           Out_B : out STD_LOGIC_VECTOR (7 downto 0);
           Out_Op : out STD_LOGIC_VECTOR (7 downto 0);
           Out_C : out STD_LOGIC_VECTOR (7 downto 0)
        );
    end component;
    
    signal Ex_A, Ex_Op, Ex_B, Ex_C : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    
    component ALU
    Port ( A : in STD_LOGIC_VECTOR (7 downto 0);
           B : in STD_LOGIC_VECTOR (7 downto 0);
           Ctrl_Alu : in STD_LOGIC_VECTOR (7 downto 0);
           S : out STD_LOGIC_VECTOR (7 downto 0);
           N : out STD_LOGIC;
           O : out STD_LOGIC;
           Z : out STD_LOGIC;
           C : out STD_LOGIC
        );
    end component;
    
    signal Ex_Ctrl_ALu, Ex_Res_Alu, Ex_FinalB : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    signal S_NFlag, S_Oflag, S_CFlag, S_ZFlag : STD_LOGIC;
    
    component Stage_Ex_Mem
    Port ( In_A : in STD_LOGIC_VECTOR (7 downto 0);
           In_B : in STD_LOGIC_VECTOR (7 downto 0);
           In_Op : in STD_LOGIC_VECTOR (7 downto 0);
           Clk : in STD_LOGIC;
           Out_A : out STD_LOGIC_VECTOR (7 downto 0);
           Out_B : out STD_LOGIC_VECTOR (7 downto 0);
           Out_Op : out STD_LOGIC_VECTOR (7 downto 0)
        );
    end component;
    
    signal Mem_A, Mem_Op, Mem_B : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    signal Mem_RW : STD_LOGIC;
    signal Mem_Addr, Mem_Data_Out, Mem_FinalB : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    
    component DataMemory
    Port ( Addr : in STD_LOGIC_VECTOR (7 downto 0);
           Data_in : in STD_LOGIC_VECTOR (7 downto 0);
           Rw : in STD_LOGIC;
           Rst : in STD_LOGIC;
           Clk : in STD_LOGIC;
           Data_out : out STD_LOGIC_VECTOR (7 downto 0)
        );
    end component;
    
    component Stage_Mem_Re
    Port ( In_A : in STD_LOGIC_VECTOR (7 downto 0);
           In_B : in STD_LOGIC_VECTOR (7 downto 0);
           In_Op : in STD_LOGIC_VECTOR (7 downto 0);
           Clk : in STD_LOGIC;
           Out_A : out STD_LOGIC_VECTOR (7 downto 0);
           Out_B : out STD_LOGIC_VECTOR (7 downto 0);
           Out_Op : out STD_LOGIC_VECTOR (7 downto 0)
        );
    end component;
    component ControlUnit is
    Port ( Op_DI, Op_EX, Op_Mem  : in STD_LOGIC_VECTOR (7 downto 0);
           A_EX, A_Mem : in STD_LOGIC_VECTOR (7 downto 0);
           B_DI : in STD_LOGIC_VECTOR (7 downto 0);
           C_DI : in STD_LOGIC_VECTOR (7 downto 0);
           CNTRL : out STD_LOGIC
        );
      end component;
    
    signal Re_A, Re_Op, Re_B : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    signal Re_W : STD_LOGIC;

    -- to control jumping and where to jump
    signal addr_to_jump : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
    signal jump : STD_LOGIC;

    signal nop_Cntrl : STD_LOGIC;
    signal OP_LI_DI : STD_LOGIC_VECTOR (7 downto 0) := (others => '0');
begin

-- instructionPointer
inst_point : IP port map ( 
    CLK=> clk, 
    Dout=> IP_out, 
    Din => addr_to_jump, 
    RST => '1',
    EN => nop_Cntrl, 
    LOAD => jump);


-- instructionMemory
MemInst : InstructionMemory PORT MAP (
    Addr => IP_out, 
    Clk => Clk,
    Inst_out => Li);

-- Stage_Li_Di
Stage1 : Stage_Li_Di PORT MAP (
    In_A => Li(23 downto 16),
    In_B => Li(15 downto 8),
    In_C => Li(7 downto 0),
    In_Op => OP_LI_DI,
    Clk => Clk,
    Out_A => Di_A,
    Out_B => Di_B,
    Out_Op => Di_Op,
    Out_C => Di_C);
    
-- Registers
StageRegisters : Registers PORT MAP (
    Addr_A => Di_B(3 downto 0), -- because the registers are on 4 bits
    Addr_B => Di_C(3 downto 0),
    Addr_W => Re_A(3 downto 0),
    W => Re_W,
    Data => Re_B,
    Rst => Rst,
    Clk => Clk,
    QA => Di_RegB,
    QB => Di_C2);
    
-- Stage DI/EX
Stage2 : Stage_Di_Ex PORT MAP (
    In_A => Di_A,
    In_B => Di_FinalB,
    In_C => Di_C2,
    In_Op => Di_Op,
    Clk => Clk,
    Out_A => Ex_A,
    Out_B => Ex_B,
    Out_Op => Ex_Op,
    Out_C => Ex_C);
    
-- ALU
Ual : ALU PORT MAP (
    A => Ex_B,
    B => Ex_C,
    Ctrl_Alu => Ex_Ctrl_ALu,
    S => Ex_Res_Alu,
    N => S_NFlag,
    O => S_OFlag,
    Z => S_ZFlag,
    C => S_CFlag);
 
-- Stage Ex/Mem
Stage3 : Stage_Ex_Mem PORT MAP (
    In_A => Ex_A,
    In_B => Ex_FinalB,
    In_Op => Ex_Op,
    Clk => Clk,
    Out_A => Mem_A,
    Out_B => Mem_B,
    Out_Op => Mem_Op);   
 
-- DataMemory
DataMem : DataMemory PORT MAP (
    Addr => Mem_Addr,
    Data_in => Mem_B,
    Rw => Mem_RW,
    Rst => Rst,
    Clk => Clk,
    Data_out => Mem_Data_Out);
    
-- Stage Mem/RE
Stage4 : Stage_Mem_Re PORT MAP (
    In_A => Mem_A,
    In_B => Mem_FinalB, 
    In_Op => Mem_Op,
    Clk => Clk,
    Out_A => Re_A,
    Out_B => Re_B,
    Out_Op => Re_Op);

-- Instruction code
    -- ADD    x"01"    
    -- MUL    x"02"
    -- SUB    x"03"
    -- DIV    x"04"
    -- COP    x"05"
    -- AFC    x"06"
    -- LOAD   x"07"
    -- STORE  x"08"
    -- INF    x"09"
    -- SUP    x"0A"
    -- EQ     x"0B"
    -- NOT    x"0C"
    -- AND    x"0D"
    -- OR     x"0E"
    -- JMP    x"0F"
    -- JMF    x"10"
    -- CAL    x"11"
    -- RET    x"12"
    -- PRI    x"13"
    -- NOP    x"FF"

-- Mux post registers 
Di_FinalB <= Di_B when 
    Di_OP = x"06" -- AFC
    else Di_RegB;
    
-- Mux post ALU
Ex_FinalB <= Ex_B when 
    Ex_Op = x"06" --AFC
    or Ex_Op = x"05" --COP
    or Ex_Op = x"07" --LOAD
    or Ex_Op = x"08" --STORE
    else Ex_Res_Alu;

-- LC pre ALU
Ex_Ctrl_ALu <= x"00" when Ex_Op = x"05" or Ex_Op = x"06" or Ex_Op = x"07" or Ex_Op = x"08" --(not using ALU)
    else Ex_Op;

-- Mux post data memory
Mem_FinalB <= Mem_B when 
    Mem_Op = x"06" --AFC
    or Mem_Op = x"05" --COP
    or Mem_Op = x"01" --ADD
    or Mem_Op = x"03" -- SUB
    or Mem_Op = x"02" -- MUL
    or Mem_Op = x"04" -- DIV
    else Mem_FinalB ; --LOAD & STORE

-- Mux pre data memory
Mem_Addr <= Mem_B when Mem_Op = x"07" --LOAD
    else Mem_A; --STORE

-- LC pre data memory
Mem_RW <= '1' when Mem_Op = x"07" --LOAD
    else '0'; --STORE
    
-- LC post Pip_Mem_Re
Re_W <= '0' when Re_Op = x"08" --STORE
    else '1'; 

CU : ControlUnit port map (
    Op_DI => Li(31 downto 24), Op_EX => Di_Op, Op_Mem => Ex_Op,
    A_EX => Di_A, A_Mem => Ex_A,
    B_DI => Li(15 downto 8),
    C_DI => Li(7 downto 0),
    CNTRL => nop_Cntrl);

 -- in case of alea : replace li(31 downto 24) by NOP
 OP_LI_DI <= X"ff" when nop_Cntrl='1' else Li(31 downto 24);

 end Behavioral;