verilog/rtl/Peripherals/Registers/OutputRegister.v

module OutputRegister #(
		parameter WIDTH = 32,
		parameter ADDRESS = 8'b0,
		parameter DEFAULT = 32'b0
	)(
		input wire clk,
		input wire rst,

		// Peripheral Bus
		input wire enable,
		input wire peripheralBus_we,
		input wire peripheralBus_oe,
		input wire[11:0] peripheralBus_address,
		input wire[3:0] peripheralBus_byteSelect,
		output wire[31:0] peripheralBus_dataRead,
		input wire[31:0] peripheralBus_dataWrite,
		output wire requestOutput,

		output wire[WIDTH-1:0] currentValue
	);
	
	localparam WRITE_ADDRESS = 4'h0;
	localparam SET_ADDRESS = 4'h4;
	localparam CLEAR_ADDRESS = 4'h8;
	localparam TOGGLE_ADDRESS = 4'hC;

	wire enableWrite = peripheralBus_address[3:0] == WRITE_ADDRESS;
	wire enableSet = peripheralBus_address[3:0] == SET_ADDRESS;
	wire enableClear = peripheralBus_address[3:0] == CLEAR_ADDRESS;
	wire enableToggle = peripheralBus_address[3:0] == TOGGLE_ADDRESS;

	wire[31:0] dataMask = {
		peripheralBus_byteSelect[3] ? 8'hFF : 8'h00,
		peripheralBus_byteSelect[2] ? 8'hFF : 8'h00,
		peripheralBus_byteSelect[1] ? 8'hFF : 8'h00,
		peripheralBus_byteSelect[0] ? 8'hFF : 8'h00
	};

	reg[WIDTH-1:0] registerValue;

	wire[31:0] maskedDataWrite = peripheralBus_dataWrite & dataMask;
	
	wire[31:0] writeData = maskedDataWrite | (registerValue & ~dataMask);
	wire[31:0] setData = registerValue | maskedDataWrite;
	wire[31:0] clearData = registerValue & ~maskedDataWrite;
	wire[31:0] toggleData = registerValue ^ maskedDataWrite;

	wire registerSelect = enable && (peripheralBus_address[11:4] == ADDRESS);
	wire we = registerSelect && peripheralBus_we && !peripheralBus_oe;
	wire oe = registerSelect && peripheralBus_oe && !peripheralBus_we;

	always @(posedge clk) begin
		if (rst) begin
			registerValue <= DEFAULT;
		end else begin
			if (we) begin
				if (enableWrite) registerValue <= writeData[WIDTH-1:0];
				else if (enableSet) registerValue <= setData;
				else if (enableClear) registerValue <= clearData;
				else if (enableToggle) registerValue <= toggleData;
			end
		end
	end

	wire[31:0] baseReadData;
	generate
		if (WIDTH == 32) begin
			assign baseReadData = registerValue;
		end else begin
			wire[32-WIDTH-1:0] zeroPadding = 'b0;
			assign baseReadData = { zeroPadding, registerValue };
		end
	endgenerate

	assign peripheralBus_dataRead = oe ? baseReadData & dataMask : 32'b0;
	assign requestOutput = oe;
	assign currentValue = registerValue;

endmodule