用持续赋值语句描述一个4选1数据选择器？？？

Question

如题所述

Answer 1

module mux4_1(out,in0,in1,in2,in3,sel) ;
input in0,in1,in2,in3;
input[1:0] sel;
output out;
assign out=sel[1]?(sel[0]?in3:in2):(sel[0]?in1:in0);
endmodule

Answer 2

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;

ENTITY DATA IS
PORT（
a,b,c: IN STD_LOGIC；
c: OUT STD_LOGIC）;
END DATA;
ARCHITECTURE Behave OF DATA IS
BEGIN
LABEL：BLOCK
VARRIBLE tmp1,tmp2,tmp3:STD_LOGIC;
BEGIN
tmp1:=a and b;
tmp2:=c and (not b);
tmp3:=tmp1 or tmp2;
y<=tmp3;
END BLOCK LABEL;

END Behave;
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