counter_4b.v

大幅噶是大法师父啊方式大法发生的发生的发生的发生的发达省份发

module counter_4b(count,carry_out,carry_in,clk,reset);

output [3:0] count;
output carry_out;
input clk,reset,carry_in;

reg [3:0] count;
reg carry_out;
initial count=0;

function [3:0] increment;
input [3:0] val;
reg [1:0] i;
reg carry;
begin
	increment=val;
	carry =carry_in;
	if(increment==4'b1111)
	   begin
	       if(carry_in==1)
	         begin
	         increment=0;	  
	         carry_out=1; 
	         end
	   end
	 else
	    begin
	      for(i=2'b0;((carry==2'b01)&&(i<=3));i=i+2'b01)
	         begin
	          increment[i]=val[i]^carry;
	          carry=val[i]&carry;
	          end	          
	       carry_out=0;
	     end      
    
end
endfunction

always @ (posedge clk )
	if(reset)
           begin
	        count=4'b0;
           //carry_out=1'b0;
           end
	else
           count=increment(count);



endmodule