Verilog_Louis/Semaine_4/UART_FIFO/IP/verilog/fifo.v

 module fifo #(
	parameter       SIZE = 16,
	parameter       WIDTH = 8
)(
    input wire              clk,
    input wire              wr_en,
    input wire[WIDTH-1:0]   wr_data,
    input wire              rd_en,
    output reg[WIDTH-1:0]   rd_data,

    output wire             full,
    output wire             empty
);

    localparam LOGSIZE = $clog2(SIZE);

    reg [WIDTH-1:0]         fifo[0:SIZE-1];
    reg [LOGSIZE-1:0]               wr_ptr;
    reg [LOGSIZE-1:0]               rd_ptr;
    reg [LOGSIZE:0]               count;

    assign full = (count == SIZE);
    assign empty = (count == 0);

    initial begin
        wr_ptr = 0;
        rd_ptr = 0;
        count = 0;
    end

    always @(posedge clk) begin // IN
        rd_data <= fifo[rd_ptr];
        if (wr_en && !full && rd_en && !empty)  begin
            fifo[wr_ptr] <= wr_data;
            wr_ptr <= (wr_ptr == SIZE - 1) ? 0 :  (wr_ptr + 1) ;
            rd_ptr <= (rd_ptr == SIZE - 1) ? 0 :  (rd_ptr + 1) ;
        end else if (wr_en && !full) begin
            fifo[wr_ptr] <= wr_data;
            wr_ptr <= (wr_ptr == SIZE - 1) ? 0 :  (wr_ptr + 1) ;
            count <= count + 1;
        end else if (rd_en && !empty) begin // OUT
            rd_ptr <= (rd_ptr == SIZE - 1) ? 0 :  (rd_ptr + 1) ;
            count <= count - 1;
        end

    end
    
endmodule