module uart_interrupt 
#(
    parameter TX_FIFO_DEPTH = 32,
    parameter RX_FIFO_DEPTH = 32
)
(
	clk_i,
	rstn_i,
	IER_i,
	RDA_i,
	CTI_i,
	error_i,
	rx_elements_i,
	tx_elements_i,
	trigger_level_i,
	clr_int_i,
	interrupt_o,
	IIR_o
);
	//parameter TX_FIFO_DEPTH = 32;
	//parameter RX_FIFO_DEPTH = 32;
	input wire clk_i;
	input wire rstn_i;
	input wire [2:0] IER_i;
	input wire RDA_i;
	input wire CTI_i;
	input wire error_i;
	input wire [$clog2(RX_FIFO_DEPTH):0] rx_elements_i;
	input wire [$clog2(TX_FIFO_DEPTH):0] tx_elements_i;
	input wire [1:0] trigger_level_i;
	input wire [3:0] clr_int_i;
	output wire interrupt_o;
	output wire [3:0] IIR_o;
	reg [3:0] iir_n;
	reg [3:0] iir_q;
	reg trigger_level_reached;
	always @(*) begin
		trigger_level_reached = 1'b0;
		case (trigger_level_i)
			2'b00:
				if ($unsigned(rx_elements_i) == 1)
					trigger_level_reached = 1'b1;
			2'b01:
				if ($unsigned(rx_elements_i) == 4)
					trigger_level_reached = 1'b1;
			2'b10:
				if ($unsigned(rx_elements_i) == 8)
					trigger_level_reached = 1'b1;
			2'b11:
				if ($unsigned(rx_elements_i) == 14)
					trigger_level_reached = 1'b1;
			default:
				;
		endcase
	end
	always @(*) begin
		if (clr_int_i == 4'b0000)
			iir_n = iir_q;
		else
			iir_n = iir_q & ~clr_int_i;
		if (IER_i[2] & error_i)
			iir_n = 4'b1100;
		else if (IER_i[0] & (trigger_level_reached | RDA_i))
			iir_n = 4'b1000;
		else if (IER_i[0] & CTI_i)
			iir_n = 4'b1000;
		else if (IER_i[1] & (tx_elements_i == 0))
			iir_n = 4'b0100;
	end
	always @(posedge clk_i or negedge rstn_i)
		if (~rstn_i)
			iir_q <= 4'b0001;
		else
			iir_q <= iir_n;
	assign IIR_o = iir_q;
	assign interrupt_o = ~iir_q[0];
endmodule