fifo_buffer.v

来自「同步及异步时序电路fifo源程序及其测试程序.rar - fifo源程序」· Verilog 代码 · 共 74 行

module FIFO_Buffer(
  Data_out,
  stack_full,
  stack_almost_full,
  stack_half_full,
  stack_almost_empty,
  stack_empty,
  Data_in,
  write_to_stack,
  read_from_stack,
  clk,rst
  );
  parameter stack_width=32;
  parameter stack_height=8;
  parameter stack_ptr_width=3;
  parameter AE_level=2;
  parameter AF_level=6;
  parameter HF_level=4;
  output [stack_width-1:0] Data_out;
  
  output                 stack_full,stack_almost_full,stack_half_full;
  output                 stack_almost_empty,stack_empty;
  input[stack_width-1:0] Data_in;
  input                  write_to_stack,read_from_stack;
  input                  clk,rst;
  
  reg[stack_ptr_width-1:0] read_ptr,write_ptr;
  
  reg[stack_ptr_width:0]   ptr_gap;
  reg[stack_width-1:0]     Data_out;
  reg[stack_width-1:0]     stack[stack_height-1:0];
  
  assign stack_full=(ptr_gap==stack_height);
  assign stack_almost_full=(ptr_gap==AF_level);
  assign stack_half_full=(ptr_gap==HF_level);
  assign stack_almost_empty=(ptr_gap==AE_level);
  assign stack_empty=(ptr_gap==0);
  
  always @(posedge clk or posedge rst)
   if(rst)begin
       Data_out<=0;
       read_ptr<=0;
       write_ptr<=0;
       ptr_gap<=0;
   end
   else if(write_to_stack &&(!stack_full)&&(!read_from_stack))begin
       stack[write_ptr]<=Data_in;
       write_ptr<=write_ptr+1;
       ptr_gap<=ptr_gap+1;
   end
   else if((!write_to_stack)&&(!stack_empty)&&read_from_stack)begin
       Data_out<=stack[read_ptr];
       read_ptr<=read_ptr+1;
       ptr_gap<=ptr_gap-1;
   end
   else if(write_to_stack &&read_from_stack&&stack_empty)begin
       stack[write_ptr]<=Data_in;
       write_ptr<=write_ptr+1;
       ptr_gap<=ptr_gap+1;
   end
   else if(write_to_stack &&read_from_stack&&stack_full)begin
       Data_out<=stack[read_ptr];
       read_ptr<=read_ptr+1;
       ptr_gap<=ptr_gap-1;
   end
   else if(write_to_stack&&read_from_stack&&(!stack_full)&&(!stack_empty))
   begin
       Data_out<=stack[read_ptr];
       stack[write_ptr]<=Data_in;
       read_ptr<=read_ptr+1;
       write_ptr<=write_ptr+1;
   end
endmodule