题解 | #流水线乘法器#

`timescale 1ns/1ns

module multi_pipe#(
	parameter size = 4
)(
	input 						clk 		,   
	input 						rst_n		,
	input	[size-1:0]			mul_a		,
	input	[size-1:0]			mul_b		,
 
 	output	reg	[size*2-1:0]	mul_out		
);

	reg [size*2-1:0] partial_products [size-1:0];
	integer i, j;
	always @(posedge clk or negedge rst_n) begin
		if (~rst_n) begin
			for (i = 0; i < size; i++) begin
				partial_products[i] <= 0;
			end
		end else begin
			for (j = 0; j < size; j++) begin
				partial_products[j] <= mul_b[j] ? mul_a << j : 0;
			end
		end
	end

	reg [size*2-1:0] sum [size-1:0];
	integer k;
	always @(posedge clk or negedge rst_n) begin
		for (k = 0; k < size; k++) begin
			if (k == 0) begin
				sum[k] = partial_products[k];
			end else begin
				sum[k] = sum[k-1] + partial_products[k];
			end
		end
	end
	
	always @(*) begin
		if (~rst_n) begin
			mul_out = 0;
		end else begin
			mul_out = sum[size-1];
		end
	end


endmodule