`timescale 1ns/1ns
module function_mod(
	input [3:0]a,
	input [3:0]b,
	
	output [3:0]c,
	output [3:0]d
);

function [3:0]	data_rev;
		input	[3:0]	data_in;
		begin	
			data_rev[0] = data_in[3];
			data_rev[1] = data_in[2];
			data_rev[2] = data_in[1];
			data_rev[3] = data_in[0];			
		end
endfunction

assign	c = data_rev(a);
assign  d = data_rev(b);

endmodule