assume cs:code ;要求dh=行号,dl=列号,cl=字属性
data segment
db 'welcome to masm!',0
data ends
code segment
start:mov ax,code
mov ds,ax
mov si,offset c7int
mov ax,20h
mov es,ax
mov di,0
mov cx,offset no-offset c7int ；将C7写入0：200处
rep movsb
mov ax,0
mov es,ax
mov es:[7ch*4],200h ;改写中断向量表
mov es:[7ch*4+2],0
mov dh,15 ;行
mov dl,16 ;列
mov cl,24h ;字属性
mov ax,data
mov ds,ax
mov si,0
int 7ch
mov ax,4c00h
int 21h
c7int:mov ax,data
mov ds,ax
mov ax,0b800h
mov es,ax
mov al,dh
mov ah,160
mul ah
add al,dl
mov di,ax
s:cmp byte ptr [si],0
je c7end
movsb
mov es:[di],cl
inc di
jmp s
c7end:iret
no: nop
code ends
end start |
