class seq_base extends uvm_sequence;
    testbench_env tb_env;

    `uvm_object_utils(seq_base)

    function new(string name = "seq_base");
        super.new(name);
    endfunction

    function void set_handles(testbench_env env);
        tb_env = env;
    endfunction

    virtual task body();
        bit ok = uvm_config_db#(testbench_env)::get(m_sequencer, "", "tb_env", tb_env);
    endtask
endclass

class seq_basic extends seq_base;
    `uvm_object_utils(seq_basic)

    function new(string name = "seq_basic");
        super.new(name);
    endfunction

    virtual task body();
        super.body();

        `uvm_info("body", $sformatf("Initiating stimulus ..."), UVM_LOW)
        fork
            begin
                d_stimulus(tb_env.tb_if.d1_if, 1);
            end
            begin
                d_stimulus(tb_env.tb_if.d2_if, 2);
            end
        join
        `uvm_info("body", $sformatf("Stimulus done."), UVM_LOW)
    endtask

    task d_stimulus(virtual design_if d_if, int inst_n);
        `uvm_info("d_stimulus", $sformatf("Inst-%0d: Initiating stimulus...", inst_n), UVM_LOW);
        repeat(20) @(negedge tb_env.tb_if.clk);
        d_if.data_in = {inst_n[15:0], 16'hd1};
        `uvm_info("d_stimulus", $sformatf("Inst-%0d: Driving data_in=0x%h", inst_n, d_if.data_in), UVM_LOW);
        repeat(50) @(negedge tb_env.tb_if.clk);
        d_if.data_in = {inst_n[15:0], 16'hd2};
        `uvm_info("d_stimulus", $sformatf("Inst-%0d: Driving data_in=0x%h", inst_n, d_if.data_in), UVM_LOW);
        repeat(20) @(negedge tb_env.tb_if.clk);
        `uvm_info("d_stimulus", $sformatf("Inst-%0d: ... stimulus done", inst_n), UVM_LOW);
    endtask
endclass

class seq_reset extends seq_base;
    `uvm_object_utils(seq_reset)

    function new(string name = "seq_reset");
        super.new(name);
    endfunction

    virtual task body();
        super.body();

        `uvm_info("body", $sformatf("Initiating reset..."), UVM_LOW)
        tb_env.tb_if.rst_n = 0;
        repeat(10) @(posedge tb_env.tb_if.clk);
        tb_env.tb_if.rst_n = 1;
        `uvm_info("body", $sformatf("Reset done."), UVM_LOW)
    endtask
endclass