`timescale 1ns/1ps

module core_tb();

initial $timeformat(-9, 2, " ns", 20);
initial begin
    $dumpfile("core_tb.vcd");
    $dumpvars(0);
end

wire dummy_out;

localparam  MEM_INST_LENGTH = 256;  // words
localparam  MEM_DATA_LENGTH = 256;  // words

localparam  MEM_DATA_BASE   = 32'h00100000;

localparam  INST_NOP        = 32'h00000013;  // nop
localparam  DATA_DEFAULT    = 32'h00000000;
localparam  DATA_INVALID    = 32'hdeadbeef;

reg clk, reset;

// Instruction memory
reg [31:0] mem_inst [0:MEM_INST_LENGTH-1];
wire [31:0] mem_inst_addr;
wire [31:0] mem_inst_idx = mem_inst_addr >> 2;
wire [31:0] mem_inst_data = mem_inst_idx < MEM_INST_LENGTH ? mem_inst[mem_inst_idx] : INST_NOP;

initial begin: mem_inst_init
    integer i;
    for (i=0; i<MEM_INST_LENGTH; i=i+1) begin
        mem_inst[i] = INST_NOP;
    end
    $readmemh("../test/text.hex", mem_inst);
end

// Data memory
reg [31:0] mem_data [0:MEM_DATA_LENGTH-1];
wire [31:0] mem_data_addr;
reg [31:0] mem_data_rdata;
wire [31:0] mem_data_wdata;
wire [3:0] mem_data_wmask;
wire mem_data_we;

initial begin: mem_data_init
    integer i;
    for (i=0; i<MEM_DATA_LENGTH; i=i+1) begin
        mem_data[i] = DATA_DEFAULT;
    end
    $readmemh("../test/data.hex", mem_data);
end

initial begin
    #0
    clk = 0;
    reset = 1;
    
    #10
    reset = 0;
    
    #5000
    reset = 1;
    $finish;
end

always #2 clk  = !clk;

core dut(
    .clk(clk),
    .reset(reset),

    .mem_inst_addr(mem_inst_addr),
    .mem_inst_data(mem_inst_data),

    .mem_data_addr(mem_data_addr),
    .mem_data_rdata(mem_data_rdata),
    .mem_data_wdata(mem_data_wdata),
    .mem_data_wmask(mem_data_wmask),
    .mem_data_we(mem_data_we),

    // .mem_data_addr(mem_data_addr),
    // .mem_data_wdata(mem_data_wdata),
    // .mem_data_rdata(mem_data_rdata),
    // .mem_data_en(mem_data_en),
    // .mem_data_we(mem_data_we),
    // .mem_data_valid(mem_data_valid),
    // .mem_data_done(mem_data_done)

    .dummy_out(dummy_out)
);

// wire axi_mem_data_awvalid;
// wire [11:0] axi_mem_data_awaddr;
// wire [2:0] axi_mem_data_awprot;
// wire axi_mem_data_awready;
// wire axi_mem_data_wvalid;
// wire [31:0] axi_mem_data_wdata;
// wire [3:0] axi_mem_data_wstrb;
// wire axi_mem_data_wready;
// wire axi_mem_data_bvalid;
// wire axi_mem_data_bready;
// wire [1:0] axi_mem_data_bresp;
// wire axi_mem_data_arvalid;
// wire [11:0] axi_mem_data_araddr;
// wire [2:0] axi_mem_data_arprot;
// wire axi_mem_data_arready;
// wire axi_mem_data_rvalid;
// wire [31:0] axi_mem_data_rdata;
// wire [1:0] axi_mem_data_resp;
// wire axi_mem_data_rready;

// axi_lite_memory axi_mem_data(
//     .ACLK(clk),
//     .ARESETn(!reset),
//     .AWVALID(axi_mem_data_awvalid),
//     .AWADDR(axi_mem_data_awaddr),
//     .AWPROT(axi_mem_data_awprot),
//     .AWREADY(axi_mem_data_awready),
//     .WVALID(axi_mem_data_wvalid),
//     .WDATA(axi_mem_data_wdata),
//     .WSTRB(axi_mem_data_wstrb),
//     .WREADY(axi_mem_data_wready),
//     .BVALID(axi_mem_data_bvalid),
//     .BREADY(axi_mem_data_bready),
//     .BRESP(axi_mem_data_bresp),
//     .ARVALID(axi_mem_data_arvalid),
//     .ARADDR(axi_mem_data_araddr),
//     .ARPROT(axi_mem_data_arprot),
//     .ARREADY(axi_mem_data_arready),
//     .RVALID(axi_mem_data_rvalid),
//     .RDATA(axi_mem_data_rdata),
//     .RRESP(axi_mem_data_resp),
//     .RREADY(axi_mem_data_rready),

//     .WB_WADDR(mem_data_waddr),
//     .WB_WPROT(),
//     .WB_WDATA(mem_data_wdata),
//     .WB_WSTRB(mem_data_wmask),
//     .WB_WVALID(mem_data_we),
//     .WB_WREADY(1'b1),

//     .WB_RADDR(mem_data_raddr),
//     .WB_RDATA(mem_data_rdata),
//     .WB_RVALID(1'b1),
//     .WB_RREADY()
// );

wire [31:0] mem_data_idx = (mem_data_addr - MEM_DATA_BASE) >> 2;
always @(*) begin
    if (mem_data_idx < MEM_DATA_LENGTH) begin
        mem_data_rdata = mem_data[mem_data_idx];
    end else begin
        mem_data_rdata = DATA_INVALID;
    end
end

always @(posedge clk) begin
    if (mem_data_idx < MEM_DATA_LENGTH) begin
        if (mem_data_we) begin
            if (mem_data_wmask[0]) begin
                mem_data[mem_data_idx][7:0] <= mem_data_wdata[7:0];
            end
            if (mem_data_wmask[1]) begin
                mem_data[mem_data_idx][15:8] <= mem_data_wdata[15:8];
            end
            if (mem_data_wmask[2]) begin
                mem_data[mem_data_idx][23:16] <= mem_data_wdata[23:16];
            end
            if (mem_data_wmask[3]) begin
                mem_data[mem_data_idx][31:24] <= mem_data_wdata[31:24];
            end
        end
    end else begin
        // ignore illegal writes
    end
end

endmodule