实验3 转移指令跳转原理及其简单应用编程

实验任务1

assume cs:code, ds:data

data segment
    x db 1, 9, 3
    len1 equ $ - x

    y dw 1, 9, 3
    len2 equ $ - y
data ends

code segment
start:
    mov ax, data
    mov ds, ax

    mov si, offset x
    mov cx, len1
    mov ah, 2
 s1:mov dl, [si]
    or dl, 30h
    int 21h

    mov dl, ' '
    int 21h

    inc si
    loop s1

    mov ah, 2
    mov dl, 0ah
    int 21h

    mov si, offset y
    mov cx, len2/2
    mov ah, 2
 s2:mov dx, [si]
    or dl, 30h
    int 21h

    mov dl, ' '
    int 21h

    add si, 2
    loop s2

    mov ah, 4ch
    int 21h
code ends
end start

运行截图：

问题①

跳转位移量：12个字节

 

从CPU的角度：当前标号的偏移地址减去位移量

问题②

跳转位移量：14个字节

 

从CPU的角度：当前标号的偏移地址减去位移量

 

实验任务2

assume cs:code, ds:data

data segment
    dw 200h, 0h, 230h, 0h
data ends

stack segment
    db 16 dup(0)
stack ends

code segment
start:  
    mov ax, data
    mov ds, ax

    mov word ptr ds:[0], offset s1
    mov word ptr ds:[2], offset s2
    mov ds:[4], cs

    mov ax, stack
    mov ss, ax
    mov sp, 16

    call word ptr ds:[0]
s1: pop ax

    call dword ptr ds:[2]
s2: pop bx
    pop cx

    mov ah, 4ch
    int 21h
code ends
end start

答：

ax=0021

bx=0026

cx=076C

 

 

实验任务3

assume cs:code, ds:data

data segment
    x db 99,72,85,63,89,97,55
    len equ $ - x
data ends

code segment
start:
    mov ax,data
    mov ds,ax

    mov si,offset x
    mov cx,len
    mov byte ptr ds:[10], 10
    
s1:
    mov ah, 0
    mov al, ds:[si]
    div byte ptr ds:[10]

    call printNumber
    call printSpace
    
    inc si
    loop s1

    mov ah,4ch
    int 21h

printNumber:
    mov bx,ax
    mov ah, 2
    
    mov dl,al
    or dl, 30h
    int 21h
    
    mov dl,bh
    or dl,30h
    int 21h
ret
printSpace:
    mov ah, 2
    mov dl,' '
    int 21h
ret

code ends
end start

 

 

实验任务4

assume ds:data, cs:code
data segment
    str db 'try'
    len equ $ - str
data ends

code segment
start:
    mov ax, data
    mov ds, ax
    mov cx, len
    mov si, offset str
    mov ax, 0b800h
    mov es, ax
    mov di, 0
    mov ah, 2

s:    call printStr
    inc si
    add di, 2
    loop s

    mov di, 3840
    mov si, offset str
    mov cx, len
    mov ah, 4

s1:    call printStr
    inc si
    add di, 2
    loop s1

    mov ax, 4c00h
    int 21h

printStr:mov al, [si]
    mov es:[di], al
    mov es:[di+1], ah
    ret

code ends
end start

 

实验任务5

assume ds:data, cs:code
data segment
    stu_no db '201983290205'
    len = $ - stu_no
data ends

code segment
start:
    mov ax, data
    mov ds, ax
    mov cx, 4000
    mov si, offset stu_no
    mov ax, 0b800h
    mov es, ax
    mov di, 0
    mov ah,17h

s:    mov al, 0
    mov es:[di], al
    mov es:[di+1], ah
    inc si
    add di, 2
    loop s

    mov di, 3840
    mov si, offset stu_no
    mov cx, 74
    mov ah, 17h
s1:    call printgang
    add di, 2
    loop s1

    mov di, 3908
    mov si, offset stu_no
    mov cx, len
    mov ah, 17h
s2:    call printStu_no
    inc si
    add di, 2
    loop s2

    mov di, 3932
    mov si, offset stu_no
    mov cx, 74
    mov ah, 17h
s3:    call printgang
    add di, 2
    loop s3

    mov ax, 4c00h
    int 21h

printStu_no:mov al, [si]
    mov es:[di], al
    mov es:[di+1], ah
    ret

printgang:mov al, 45
    mov es:[di], al
    mov es:[di + 1], ah
    ret

code ends
end start