control.v

/*  control.v  */
module control(
	input	wire	[5:0] opcode,
	output reg	[3:0] EX,
	output reg	[2:0] M,
	output reg	[1:0] WB
   );
	 
	parameter RTYPE	= 6'b000000; 
	parameter LW		= 6'b100011;
	parameter SW		= 6'b101011;
	parameter BEQ		= 6'b000100;
	parameter NOP		= 6'b100000;	
	
	initial begin
		EX <= 4'b0000;
		M <= 3'b000;
		WB <= 2'b00;
	end

	always@* begin
		case (opcode)
			RTYPE:
				begin
					EX <= 4'b1100;
					M  <= 3'b000; 
					WB <= 2'b10;
				end
			LW:
				begin
					EX <= 4'b0001;
					M  <= 3'b010; 
					WB <= 2'b11;
				end
			SW: 
			  begin
					EX <= 4'bz001;
					M  <= 3'b001; 
					WB <= 2'b0z;
			  end
			BEQ: 
				begin
					EX <= 4'bz010;
					M  <= 3'b100; 
					WB <= 2'b0z;
				end
			NOP:
				begin  
					EX <=4'b1000; 
					M <=3'b000; 
					WB <=2'b00;
				end
			default:	$display ("Opcode not recognized.");
		endcase
	end
endmodule // control