(1)
mov ax,1
mov ds,ax
mov ax,[0000]  ;ax=8070H
mov bx,[0001]  ;bx=f080H
mov ax,bx      ;ax=f080H
mov ax,[0000]  ;ax=8070H
mov bx,[0002]  ;bx=30f0H
add ax,bx      ;ax=b160H
add ax,[0004]  ;ax=124fH
mov ax,0       ;ax=0000H
mov al,[0002]  ;ax=00f0H
mov bx,0       ;bx=0000H
mov bl,[000c]  ;bx=0066H
add al,bl      ;ax=0056H
（2）
mov ax,2000H   ;cs=2000H,ip=3,ax=2000H
mov ds,ax      ;cs=2000H,ip=5,ds=2000H
mov ax,[0008]  ;cs=2000H,ip=8,ax=c389H
mov ax,[0002]  ;cs=2000H,ip=0BH,ax=ea66H

没区别，由CS和IP指向的内存区域就当成程序，由DS指向的内存区域就当成数据。