registers.v

簡易MIPS CPU程式碼 此CPU包含 shift add sub and or stl beq lw sw 等功能

module registers (clk, RegWrite, RN1, RN2, WN, RD1, RD2, WD);
  input clk;
  input RegWrite;
  input [4:0] RN1, RN2, WN;
  input [31:0] WD;
  output [31:0] RD1, RD2;

  reg [31:0] RD1, RD2;
  reg [31:0] file_array [31:1];

  always @(RN1 or file_array[RN1])
  begin   
    if (RN1 == 0) RD1 = 32'd0;
    else RD1 = file_array[RN1];
  end

  always @(RN2 or file_array[RN2])
  begin
    if (RN2 == 0) RD2 = 32'd0;
    else RD2 = file_array[RN2];
  end

  always @(posedge clk) 
    if (RegWrite && (WN != 0))
    begin
      file_array[WN] <= WD;
    end
endmodule