汇编程序编写：
assume cs:code
code segment
mov ax,2000h
mov ss,ax
mov sp,0
add sp,10
pop ax
pop bx
push ax
push bx
pop ax
pop bx
mov ax,4c00h
int 21h
code ends

寄存器：ax bx ss sp

ax, bx, ss, sp, 2000:10 x, 2000:12 y
step0:mov ax,2000h

ax=2000h, bx, ss, sp, 2000:10 x, 2000:12 y
step1:mov ss,ax

ax=2000h, bx, ss=2000h, sp, 2000:10 x, 2000:12 y
step2:mov sp,0

ax=2000h, bx, ss=2000h, sp=0, 2000:10 x, 2000:12 y
step3:add sp,10

ax=2000h, bx, ss=2000h, sp=10, 2000:10 x, 2000:12 y
step4:pop ax

ax=x, bx, ss=2000h, sp=12, 2000:10 x, 2000:12 y
step5:pop bx

ax=x, bx=y, ss=2000h, sp=14, 2000:10 x, 2000:12 y
step6:push ax

ax=x, bx=y, ss=2000h, sp=12, 2000:10 x, 2000:12 x
step7:push bx

ax=x, bx=y, ss=2000h, sp=10, 2000:10 y, 2000:12 x
step8:pop ax

ax=y, bx=y, ss=2000h, sp=12, 2000:10 x, 2000:12 y
step9:pop bx

ax=y, bx=x, ss=2000h, sp=14, 2000:10 x, 2000:12 y