`include "Decoder.v"

module Decoder_tb;

    reg [31:0] instruction;

    // ALU wires
    wire branch_op;
    wire [31:0] imm;
    wire operand_B_sel;
    wire [5:0] ALU_control;

    // Regfile wires
    wire [4:0] write_addr;    // N.B. write_addr.. destination reg address
    wire [4:0] rs1_addr;      // rs1_addr
    wire [4:0] rs2_addr;      // rs2_addr   
    wire we;

    // Memory wires
    wire mem_we;
   // wire [4:0] write_transfer;    


    Decoder uut(
        .instruction(instruction),
        .branch_op(branch_op),
        .imm(imm),
        .operand_B_sel(operand_B_sel),
        .ALU_control(ALU_control),
        .write_addr(write_addr),
        .rs1_addr(rs1_addr),
        .rs2_addr(rs2_addr),
        .we(we),
        .mem_we(mem_we),
       // .write_transfer(write_transfer)
    );

    task print_param;
        begin
            $display("Time: %0d", $time);
            $display("instruction: %0b", instruction);
            $display("rs1_addr: %0b", rs1_addr);
            $display("rs2_addr: %0b", rs2_addr);
            $display("write_addr: %0b", write_addr);
            $display("we: %0b", we);
            $display("branch_op: %0b", branch_op);
            $display("imm: %0b", imm);
            $display("operand_B_sel: %0b", operand_B_sel);
            $display("ALU_control: %0b", ALU_control);
            $display("mem_we: %0b", mem_we);
          //  $display("write_transfer -- not yet assigned: %0b", write_transfer);
            $display("--------------------------------------------------------");
            $display("\n");
        end
    endtask

    initial begin
        $dumpfile("Decoder_waveform.vcd");
        $dumpvars(0, Decoder_tb);
        $display("--------------------------------------------------------");
        instruction = 32'b0;

        #10
        $display("NO Operation: add zero, zero, 0");
        print_param();
        instruction = 32'b0000000_01100_01011_000_01101_0110011;

        #10
        $display("add a3, a1, a2");
        print_param();
        instruction = 32'b0100000_01111_01110_000_10000_0110011;

        #10
        $display("sub a6, a4, a5");
        print_param();
        instruction = 32'b0100000_01111_01110_100_10000_0110011;

        #10
        $display("xor a6, a4, a5");
        print_param();
        instruction = 32'b0000000_01100_01011_100_01010_0010011;

        
        #10
        $display("xori a0, a1, imm");
        print_param();
        instruction = 32'b1100000_01100_01011_101_11111_1100011;

        #10
        $display("bge a4, a5");
        print_param();

        // to add more load and store tests
        // don't forget the sel flag


    end

endmodule