方法一:布尔表达式 LBRARY EER USE IEEE STD LOG1C 1164.ALLY ENTITY ands PORT (a, b, C: IN STD_LOGIC; y OUT STD_LOGICE END and3- ARCHITECTURE and3 1 OF and3 s BEGIN y <=a AND b AND c) END and3_1方法一：布尔表达式 LIBRARY IEEE; USE IEEE.STD_LOG1C_1164.ALL; ENTITY and3 IS PORT (a, b, c : IN STD_LOGIC; y : OUT STD_LOGIC); END and3; ARCHITECTURE and3_1 OF and3 IS BEGIN y <= (a AND b AND c) ; END and3_1;