汇编实验15

eol75999

assume cs:code
code segment
start:
mov ax,cs
mov ds,ax
mov ax,0
mov es,ax

mov si,offset int9
mov di,204

mov cx,offset int9end-offset int9

cld
rep movsb;写进0:204

push es:[9*4]
pop es:[200]
push es:[9*4+2]
pop es:[202]

cli

mov word ptr es:[9*4],204
mov word ptr es:[9*4+2],0

sti

mov ax,4c00h
int 21h


int9:
push ax
push bx
push cx
push es

in al,60h
pushf
call dword ptr cs:[200]

cmp al,1eh+80h;判断是否是a的断码
jne int9ret
mov ax,0b800h
mov es,ax
mov cx,4000
mov bx,0

s:
mov byte ptr es:[bx],'A'     
inc byte ptr es:[bx+1]
add bx,2
loop s

int9ret:
pop es
pop cx
pop bx
pop ax
iret

int9end: nop

code ends
end start