指出下列指令中的非法指令:
(1)MOV BX,AL
(2)MOV CS,2000H
(3)PUSH 4567H
(4)XCHG VAR1,VAR2
(5)ADD AL,148H
(6)MOV DS,2000H
(7)MOV BH,SI
(8)SUB 38H,AL
若DS=3000H,BP=2000H,SI=1000H,[32000H]=00H,[32001H]=40H,SS=3000H,[31000H]=20H,[31001H]=60H,[33000H]=50H,[33001H]=60H,说明下列各条指令执行后,AX中的内容是什么?并说明各条指令中源操作数的寻址方式。
(1)MOV AX,DS
(2)MOV AX,[2000H]
(3)MOV AX,[SI]
(4)MOV AX,[BP]
(5)MOV AX,[BP+SI]