汇编学习（八）8086汇编拾遗 (7)-蒲公英云

汇编学习（八）8086汇编拾遗 (7)

int 中断指令
使用方式：
int n.  n 为中断类型码，它的功能是引发中断，n 为引发的中断号。
先写一个中断程序的例子吧，安装中断7ch 中断例程，计算一个字型数的平方。
assume cs:code code segment start: mov ax,cs mov ds,ax mov si,offset sets mov di,200h mov ax,0 mov es,ax mov cx,offset sets0 - offset sets 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 sets: mul ax iret sets0:nop code ends end start

再来一个转换字符串的中断。功能：将一个全是子母，以0结尾的字符串转换为大写。

assume cs:code
code segment
    start:
        mov ah,2
        mov bh,0
        mov dh,5
        mov dl,12
        int 10h
        mov ah,9
        mov al,'a'
        mov bl,11001010b
        mov bh,0
        mov cx,3
        int 10h
        mov ax,4c00h
        int 21h
code ends
end start

使用int 模拟 loop

assume cs:code
code segment
    start:
        mov ax,cs
        mov ds,ax
        mov ax,0
        mov es,ax
        mov si,200h
        mov di,offset se
        mov cx,offset se0 - offset se
        rep movsb
        mov ax,0
        mov es,ax
        mov word ptr es:[7ch*4],0
        mov word ptr es:[7ch*4+2],200h
        mov ax,4c00h
        int 21h
    se:
        push bp
        mov bp,sp
        dec cx
        jcxz ll
        add [bp+2],bx
    ll:
        pop bp
        iret
    se0:
        nop
code ends
end start

编写7CH中断实现jmp near ptr s 功能：

assume cs:code
data segment
    db 'conversion',0
data ends
code segment
    start:
        mov ax,cs
        mov ds,ax
        mov si,offset se
        mov ax,0
        mov es,ax
        mov di,200h
        mov cx,offset se0 - offset se 
        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,data
        mov ds,ax
        mov si,0
        mov ax,0b800h
        mov es,ax
        mov di,12*160
      s:
        cmp byte ptr [si],0
        je ok
        mov al,[si]
        mov es:[di],al
        inc si
        add di,2
        mov bx,offset s - offset ok
        int 7ch
     ok:
        mov ax,4c00h
        int 21h
    se:
        push bp
        mov  bp,sp
        add  [bp+2],bx
        pop bp
        iret
    se0:nop
code ends
end start

编写并安装7ch中断，直到0结束的字符串

assume cs:code
data segment
    db 'weclome to linux world!',0
data ends
code segment
    start:
        mov ax,cs                ;添加中断代码
        mov ds,ax
        mov si,offset se 
        mov di,200h
        mov ax,0
        mov es,ax
        mov cx,offset se0 - offset se 
        cld 
        rep movsb
        mov ax,0                 ;设置中断号
        mov es,ax
        mov word ptr es:[7ch * 4],200h
        mov word ptr es:[7ch * 4 + 2],0
        mov dh,10                ;测试代码
        mov dl,10
        mov cl,2
        mov ax,data
        mov ds,ax
        mov si,0
        int 7ch
        mov ax,4c00h
        int 21h
    se:
        mov al,160           ;设置es:0b800h         
        mul dh
        add dl,dl
        mov dh,0
        add ax,dx
        mov di,ax
        mov ax,0b800h
        mov es,ax
      s:
        mov al,ds:[si]       ;打印字符
        mov ah,0
        cmp ax,0
        je f
        mov ah,cl 
        mov es:[di],ax
        inc si
        inc di
        inc di
        jmp s
      f:
        iret
    se0:nop
code ends
end start

编写7C 中断，打印80个!

assume cs:code
code segment
    start:
        mov ax,cs                       ;安装中断
        mov ds,ax
        mov si,offset lp
        mov ax,0
        mov es,ax
        mov di,200h
        mov cx,offset lpend - offset lp
        cld
        rep movsb
        mov word ptr es:[7ch*4],200h
        mov word ptr es:[7ch*4 + 2],0
        mov ax,0b800h                   ;设置es
        mov es,ax
        mov di,160*12
        mov bx,offset s -offset se 
        mov cx,80
        s:
            mov byte ptr es:[di],'!'
            add di,2
            int 7ch
        se:
            nop
        mov ax,4c00h
        int 21h
        lp:
            push bp                     ;循环 
            dec cx
            jcxz f
            mov bp,sp
            add [bp+2],bx
        f:
            pop bp
            iret
        lpend:nop
code ends
end start