module test_Pipelining
(
	input CLK,
	input RSTn,
	output reg [7:0]result
);

reg [7:0]x,y;
reg [3:0]i;
always @(posedge CLK or negedge RSTn)
	if(!RSTn)
	begin
		x <= 8'd0;
		y <= 8'd0;
		i <= 4'd0;
	end
	else 
		case(i)
			0:
			begin
				x <= 8'd1;
				y <= 8'd1;
				i <= i + 1'b1;
			end
			1:
			begin
				x <= 8'd2;
				y <= 8'd2;
				i <= i + 1'b1;
			end
			2:
			begin
				x <= 8'd3;
				y <= 8'd3;
				i <= i + 1'b1;
			end
			3:
			begin
				x <= 8'd0;
				y <= 8'd0;
				i <= i;
			end
		endcase


	
	reg [7:0]result0;
	always @(posedge CLK or negedge RSTn)
		if(!RSTn)
		begin
			result0 <= 8'd0;
		end
		else
		begin
			result0 <= x + y;
		end

	reg [7:0]result1;
	always @(posedge CLK or negedge RSTn)
		if(!RSTn)
		begin
			result1 <= 8'd0;
		end
		else
		begin
			result1 <= result0 * 8'd3;
		end

	always @(posedge CLK or negedge RSTn)
		if(!RSTn)
		begin
			result <= 8'd0;
		end
		else
		begin
			result <= result1 + 8'd5;
		end

endmodule

将公式(x + y) * 3 + 5,猜分成3个步骤
1、result0 <= x + y;
2、result1 <= result0 * 8'd3;
3、result <= result1 + 8'd5;

result0延时x，y一个周期；
result1延时result0一个周期；
result延时result1一个周期；

那么，result延时x，y 3个周期；且一一对应！！

因为x，y是源源不断的输入（每个周期改变一次）
所以 result在3个周期后，是源源不断的输出～～！！

总结：1、潜伏周期 = 步骤数。
2、最后一个数据的输入时刻 + 潜伏周期数（或者步骤数） 就是整个流水操作的完成时刻。

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