//?????
//---------------------------------------------------------------
module register(opc_iraddr,data,ena,clk1,rst);
output [15:0] opc_iraddr;
input [7:0] data;
input ena, clk1, rst;
reg [15:0] opc_iraddr;
reg  state;

always @(posedge clk1)
begin
if(rst)
begin
opc_iraddr<=16'b0000_0000_0000_0000;
state<=1'b0;
end
else
begin
if(ena)		//???????????load_ir???
begin		//???????8????????
casex(state)	//?????????
1'b0:  begin
 opc_iraddr[15:8]<=data;
 state<=1;
  end
1'b1:  begin
 opc_iraddr[7:0]<=data;
 state<=0;
  end
default:  begin
opc_iraddr[15:0]<=16'bxxxxxxxxxxxxxxxx;
state<=1'bx;
end
endcase
end
else
state<=1'b0;
end
end
endmodule
//--------------------------------------------------------