需要从MASM转换到NASM

Posted 2021-03-29

附加文件：文件dosbox_003.png（5.722 KB）编写一个NASM，它将：

在一行显示您的姓名。 （使用int 21h，函数9.回车和换行的字符分别为0Dh和0Ah。）在下一行，显示提示（再次使用int 21h，function9）并从键盘读取三个字符（使用int 21h，fcn 1.）将字符存储在适当标记的字节变量中。打印三个字符，每行一个（根据您的实现方式，使用int 21h，函数9或函数2，您的选择。）使用NASM组装程序并使用DOSBox执行它。

用命令提示符组装

鉴于此代码（错误加粗和突出显示行）我有这些错误

C:NASM>nasm bal-lab2.asm -o bal-lab2.com
bal-lab2.asm:5: error: attempt to define a local label before any non-local 
labels
bal-lab2.asm:5: error: parser: instruction expected
bal-lab2.asm:6: error: attempt to define a local label before any non-local 
labels
bal-lab2.asm:6: error: parser: instruction expected
bal-lab2.asm:7: warning: label alone on a line without a colon might be in 
error [-w+orphan-labels]
bal-lab2.asm:7: error: attempt to define a local label before any non-local 
labels
bal-lab2.asm:17: warning: label alone on a line without a colon might be in 
error [-w+orphan-labels]
bal-lab2.asm:18: error: parser: instruction expected
bal-lab2.asm:127: error: symbol `main' redefined
bal-lab2.asm:127: error: parser: instruction expected
bal-lab2.asm:128: error: parser: instruction expected

用这个代码

;ff
;ff
;ff

.model small line ***LINE 5***
.stack 100h ***LINE 6***
.data ***LINE 7***  
nameString db 'my name here $' ;replace by your name
prompt1 db 'Enter first character : $' ;ask for character
prompt2 db 'Enter second character : $' ;ask for character
prompt3 db 'Enter third character : $' ;ask for character

character1 DB ? ;memory to store character
character2 DB ? ;memory to store character
character3 DB ? ;memory to store character

.code ***LINE 17**
main proc ***LINE 18***


mov ax,@data ;move data address to ax
mov ds,ax ;move ax to data segment  


lea dx , nameString ;move content to dx

mov ah,9 ;ask to print array of string
int 21h

mov dx,10 ;print 

mov ah,2
int 21h  

mov dx,13 ;cursor at first position
mov ah,2
int 21h

lea dx , prompt1 ;if use lea no need to use offset

mov ah,9 ;print prompt
int 21h  
;ask for character input
mov ah,1
int 21h

mov character1,al ; move to labled memory


mov dx,10 ;print 

mov ah,2
int 21h  

mov dx,13 ;cursor at first position
mov ah,2
int 21h

lea dx , prompt2 ;if use lea no need to use offset

mov ah,9 ;print prompt
int 21h  
;ask for character input
mov ah,1
int 21h

mov character2,al ; move to labled memory


mov dx,10 ;print 

mov ah,2
int 21h  

mov dx,13 ;cursor at first position
mov ah,2
int 21h

lea dx , prompt3 ;if use lea no need to use offset

mov ah,9 ;print prompt
int 21h  
;ask for character input
mov ah,1
int 21h

mov character3,al ; move to labled memory  


mov dx,10 ;print 

mov ah,2
int 21h  

mov dx,13 ;cursor at first position
mov ah,2
int 21h

mov dl,character1 ;move character value to dl for print
mov ah,2
int 21h

mov dx,10 ;print 

mov ah,2
int 21h  

mov dx,13 ;cursor at first position
mov ah,2
int 21h

mov dl,character2 ;move character value to dl for print
mov ah,2
int 21h


mov dx,10 ;print 

mov ah,2
int 21h  

mov dx,13 ;cursor at first position
mov ah,2
int 21h

mov dl,character3 ;move character value to dl for print
mov ah,2
int 21h


mov ah,4ch
int 21h
main endp ***LINE 127***
end main ***LINE 128***

错误突出显示，并且线条太过感激任何帮助，我对汇编语言非常新

答案

• 删除前7行程序并替换为org 0x100
• 将.data中的所有内容移动到文件末尾。 COM文件中不需要的部分。
• 将所有出现的qazxsw poi更改为qazxsw poi
• 删除第17到22行mov ax，@ data和mov ds，不需要ax
• 你使用db ?的每个地方都改为db 0
• 将lea的所有实例更改为mov

进行这些更改，你的程序将工作，我使用DOSBox 0.74进行测试，输出看起来像这样;

character?

这是您为NASM修改的程序，以及一些个人调整，如缩短标签

[character?]