牛客进阶题目15：自动贩售机2

跟上题基本类似，加了个sel选择

`timescale 1ns/1ns

module seller2(
	input wire clk  ,
	input wire rst  ,
	input wire d1 ,
	input wire d2 ,
	input wire sel ,
	
	output reg out1,
	output reg out2,
	output reg out3
);
//*************code***********//
reg[2:0] d_cnt ;
wire	 d_cur ;

assign d_cur = d1 ? d1 : (d2 ? d2 : 0);

always @(posedge clk or negedge rst) begin
	if(!rst)
		d_cnt <= 'd0 ;
	else if((d_cnt+d_cur>=3 & !sel)|(d_cnt+d_cur>=5 & sel))
		d_cnt <= d_cur ;
	else if(d1)
		d_cnt <= d_cnt + 1 ;
	else if(d2)
		d_cnt <= d_cnt + 2	;
	else 
		d_cnt <= d_cnt ;
end
always @(posedge clk or negedge rst) begin
	if(!rst) begin
		out1 <= 'd0 ;
		out2 <= 'd0 ;
		out3 <= 'd0 ;
	end
	else if(!sel & (d_cnt+d_cur >= 3)) begin
		out1 <= 1'b1 ;
		out3 <= d_cnt+d_cur - 3 ;
		out2 <= 1'b0 ;
	end
	else if(sel & (d_cnt+d_cur >= 5)) begin
		out1 <= 1'b0 ;
		out3 <= d_cnt+d_cur - 5 ;
		out2 <= 1'b1 ;
	end
	else begin		
		out1 <= 1'b0 ;
		out2 <= 'd0 ;
		out3 <= 1'b0 ;
	end
end
//*************code***********//
endmodule