freelist verilog实现

以下是一个基本的freelist Verilog实现：

module freelist (
  input clk, //时钟
  input reset, //重置信号
  input [31:0] new_address, //新地址
  input [31:0] free_address, //空闲地址
  output [31:0] allocated_address, //分配的地址
  output [31:0] updated_free_address, //更新后的空闲地址
  output full, //freelist是否已满
  output empty //freelist是否为空
);

  parameter SIZE = 1024; //freelist的大小
  parameter ADDR_WIDTH = $clog2(SIZE); //地址宽度
  parameter DATA_WIDTH = 32; //数据宽度

  reg [ADDR_WIDTH-1:0] head; //链表头
  reg [ADDR_WIDTH-1:0] tail; //链表尾
  reg [ADDR_WIDTH-1:0] prev; //当前节点的前一个节点
  reg [ADDR_WIDTH-1:0] curr; //当前节点
  reg [ADDR_WIDTH-1:0] next; //当前节点的下一个节点
  reg [ADDR_WIDTH-1:0] new_node; //新节点
  reg [ADDR_WIDTH-1:0] free_node; //空闲节点
  reg [ADDR_WIDTH-1:0] allocated_node; //分配的节点
  reg [DATA_WIDTH-1:0] data [0:SIZE-1]; //freelist数据存储

  assign full = (tail == head-1) || (head == 0 && tail == SIZE-1); //freelist是否已满
  assign empty = (head == tail); //freelist是否为空

  //重置
  always @ (posedge clk) begin
    if (reset) begin
      head <= 0;
      tail <= SIZE-1;
      prev <= 0;
      curr <= 0;
      next <= 0;
      new_node <= 0;
      free_node <= 0;
      allocated_node <= 0;
      data <= 0;
    end
  end

  //分配
  always @ (posedge clk) begin
    if (!reset) begin
      if (new_address != 0 && !full) begin
        allocated_node <= tail;
        allocated_address <= data[tail];
        if (tail == 0) begin
          tail <= SIZE-1;
        end else begin
          tail <= tail-1;
        end
      end
    end
  end

  //释放
  always @ (posedge clk) begin
    if (!reset) begin
      if (free_address != 0 && !empty) begin
        free_node <= head;
        data[head] <= free_address;
        if (head == SIZE-1) begin
          head <= 0;
        end else begin
          head <= head+1;
        end
      end
    end
  end

  //插入
  always @ (posedge clk) begin
    if (!reset) begin
      if (new_address != 0 && !full) begin
        new_node <= tail;
        data[tail] <= new_address;
        if (tail == 0) begin
          tail <= SIZE-1;
        end else begin
          tail <= tail-1;
        end
      end
    end
  end

  //删除
  always @ (posedge clk) begin
    if (!reset) begin
      if (free_address != 0 && !empty) begin
        prev <= head;
        curr <= head;
        next <= head+1;
        while (curr != free_node) begin
          prev <= curr;
          curr <= next;
          next <= next+1;
          if (next == SIZE) begin
            next <= 0;
          end
        end
        if (free_node == head) begin
          head <= head+1;
        end else if (free_node == tail) begin
          tail <= tail-1;
        end else begin
          data[prev] <= data[curr];
          curr <= prev;
        end
      end
    end
  end

  assign updated_free_address = data[head]; //更新后的空闲地址

endmodule

该实现包含四个主要操作：分配、释放、插入和删除。每个操作都有一个相应的always块，以确保在时钟上升沿时，该操作会被执行。其中，分配和释放操作分别将新地址和空闲地址存储到freelist中，并将分配的地址和更新后的空闲地址输出。插入和删除操作用于将新节点插入到freelist中或从freelist中删除空闲节点。在所有操作中，都需要检查freelist是否已满或为空，并将full和empty标志输出。