题解 | #多功能数据处理器#

`timescale 1ns/1ns
module data_select(
	input clk,
	input rst_n,
	input signed[7:0]a,
	input signed[7:0]b,
	input [1:0]select,
	output reg signed [8:0]c
);
always@(posedge clk or negedge rst_n)begin
	if(!rst_n)begin
		c<=9'b0;
	end
	else begin
		case(select)
		0:begin
			c<=a;
		end
		1:begin
			c<=b;
		end
		2:begin
			if(a[7]==b[7])
				c<=a+b;
			else 
				c<=(a[6:0]>b[6:0])?{{a[7]},{a[6:0]-b[6:0]}}:{{b[7]},{b[6:0]-a[6:0]}};
		end
		3:begin
			if(a[7]==b[7])
				c<=(a[6:0]>b[6:0])?(a-b):{{-a[7]},{b[6:0]-a[6:0]}};
			else
				c<={{a[7]},{a[6:0]+b[6:0]}};
		end
		endcase
	end
end
endmodule