(程序分析题, 5分)分析下面程序功能，并说明工作过程LIBRARY IEEE; USE IEE
E:STD_LOGIC_1164.ALL; USE IEE
E:STD_LOGIC_UNSIGNE
D:ALL;ENTITY SCOUNT IS PORT ( CLK: IN STD_LOGIC; CLR: IN STD_LOGIC;
D: IN STD_LOGIC; Q: BUFFER STD_LOGIC_VECTOR (7 DOWNTO 0));END SCOUNT;ARCHITECTURE a OF SCOUNT IS BEGINProcess(CLK) BEGIN IF CLK'EVENT AND CLK='1' THEN IF CLR='0' THEN Q<="00000000"; ELSIF D='1' THEN Q<=Q+1; ELSE Q<=Q-1; END IF; END IF; END PROCESS;END a;