CDi_MiSTer/rtl/mpeg/fmv/decoder_firmware_memory.sv

// Quartus Prime SystemVerilog Template
//
// True Dual-Port RAM with different read/write addresses and single read/write clock
// and with a control for writing single bytes into the memory word; byte enable

// Read during write produces old data on ports A and B and old data on mixed ports
// For device families that do not support this mode (e.g. Stratix V) the ram is not inferred

module decoder_firmware_memory #(
    parameter int BYTE_WIDTH = 8,
    ADDRESS_WIDTH = 12,
    BYTES = 4,
    DATA_WIDTH_R = BYTE_WIDTH * BYTES
) (
    input [ADDRESS_WIDTH-1:0] addr1,
    input [ADDRESS_WIDTH-1:0] addr2,
    input [BYTES-1:0] be1,
    input [BYTES-1:0] be2,
    input [DATA_WIDTH_R-1:0] data_in1,
    input [DATA_WIDTH_R-1:0] data_in2,
    input we1,
    we2,
    clk,
    output [DATA_WIDTH_R-1:0] data_out1,
    output [DATA_WIDTH_R-1:0] data_out2
);
    localparam RAM_DEPTH = 13500 >> 2;

    // model the RAM with two dimensional packed array
    logic [BYTES-1:0][BYTE_WIDTH-1:0] ram[0:RAM_DEPTH-1];

    initial $readmemh("../rtl/mpeg/fmv/firmware.mem", ram);

    reg [DATA_WIDTH_R-1:0] data_reg1;
    reg [DATA_WIDTH_R-1:0] data_reg2;

    // port A
    always_ff @(posedge clk) begin
        if (we1) begin
            // edit this code if using other than four bytes per word
            if (be1[0]) ram[addr1][0] <= data_in1[7:0];
            if (be1[1]) ram[addr1][1] <= data_in1[15:8];
            if (be1[2]) ram[addr1][2] <= data_in1[23:16];
            if (be1[3]) ram[addr1][3] <= data_in1[31:24];
        end
        data_reg1 <= ram[addr1];
    end

    assign data_out1 = data_reg1;

    // port B
    always_ff @(posedge clk) begin
        if (we2) begin
            // edit this code if using other than four bytes per word
            if (be2[0]) ram[addr2][0] <= data_in2[7:0];
            if (be2[1]) ram[addr2][1] <= data_in2[15:8];
            if (be2[2]) ram[addr2][2] <= data_in2[23:16];
            if (be2[3]) ram[addr2][3] <= data_in2[31:24];
        end
        data_reg2 <= ram[addr2];
    end

    assign data_out2 = data_reg2;

endmodule : decoder_firmware_memory