如何在.COM可执行文件中以相反的顺序打印字符串? [英] How to print a string in reverse order in a .COM executable?

问题描述

我刚开始学习汇编语言，我正尝试以相反的顺序打印"hello world"，这意味着"dlrow olleh".问题是我只得到第一个字母作为输出，并且顺序仍然不变根本！作为一个新手，很多事情对我来说是未知的，我正在做很多错误，由于缺乏知识而无法识别它们，因此任何带有适当解释的答案将不胜感激！这是我的代码:

I have just started to learn assembly language and i am trying to print "hello world" in reverse order that means "dlrow olleh".the problem is i am getting only 1st letter as output and the order is still same no change at all!As a newbie many thing is unknown to me and i am doing lots of mistakes and i am unable to identify them due to lack of knowledge.So any answer with proper explanation will be appreciated!Here is my code:

name "hi" ; can anybody explain what is the use of this?

org 100h

jmp start       ; jump over data declaration

msg    db      "1Hello, World!",0;last character           
msg1   db      "1"

Mov   SI,13;lenght of the string
start: 

Mov  AL,msg[SI]
DEC SI 

Mov  ah ,0eh
int 10h   
mov BL,msg1

CMP msg[SI],BL;comparing to get the end of the string
je stop

jmp start                     

stop:
mov     ah, 0 
int     16h      ; wait for any key....
ret ; return to operating system.

我只输出第一个字母"1"，但是我希望以相反的顺序得到整个字符串

i am getting output only "1" which is the first letter,but i expected to get the whole string in reverse order

推荐答案

jmp start       ; jump over data declaratio
...
Mov   SI,13;lenght of the string
start: 

问题出在这里-您没有初始化寄存器si

here is the problem - you're not initializing register si

您需要使用以下内容:

jmp init       ; jump over data declaratio
...
init:
Mov   SI,13;lenght of the string
start: 

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