王爽汇编 Lab 13 Question 1, 用两个程序实现

如果要用两个程序实现， 必须用实DOS，或者用DosBox。 我是用DosBox实现的。

安装和中断例程代码如下

assume cs:code 
code segment
start:    ;installtion
        mov ax, cs
        mov ds, ax
        mov si, offset shwtxt
        mov ax, 0
        mov es, ax
        mov di, 200h
        mov cx, offset shwtxtend-offset shwtxt
        cld
        rep movsb
        
        mov ax, 0
        mov es, ax
        mov word ptr es:[7ch*4], 200h
        mov word ptr es:[7ch*4+2],0  
        mov ax, 4c00h
        int 21h
        
shwtxt:    push cx
        push si
        push bx
        push ax 
        mov ah, 160 
        mul dh
        mov bx, ax 
        mov ah, 32
        mul dl
        Add ax, bx         
        mov di, ax
        pop ax
        pop bx
        mov ax, 0b800h
        mov es, ax 
        mov al, cl
nxtchr:    mov cl, [si]        
        mov ch, 0
        jcxz ok 
        mov ch, al
        
        mov es:[di], cx
        add di, 2
        inc si
        jmp short nxtchr 
    ok:    pop si
        pop cx    
        iret 
shwtxtend: nop
code ends

end start  

运行和使用例程的程序如下

assume cs:code
data segment
    db "welcome to masm!",0
data ends
code segment
start:    mov dh, 12
        mov dl, 8
        mov cl, 01110001B
        mov ax, data
        mov ds, ax
        mov si, 0
        int 7ch
        
        mov ax, 4c00h
        int 21h 
code ends

end start