7、OWNTO0));ENDENTITYQDJB;ARCHITECTUREARTOFQDJBISsignala_1,b_1,c_1,d_1:STD_LOGIC; BEGIN PROCESS(CLR,A,B,C,D)IS BEGINIFCLR='1'THENSTATES<="0000";a_1<='0';b_1<='0';c_1<='0';d_1<='0';--清零ELSIFa_1='1'orb_1='1'orc_1='1'ord_1='1'thennull;--锁存,当有一组选中时其他组再抢答没作用ELS