NASM：未指定操作大小(NASM: operation size not specified)

NASM：未指定操作大小 - IT屋-程序员软件开发技术分享社区 (it1352.com)

2020-05-16  IT屋

 

百度翻译此文   有道翻译此文

 

 

• 原文

 

I wrote this code in emu8086 and it goes well in the emulator but when I'm trying to compile it with NASM it's throwing me up the error: "operation size not specified", help someone?

add bx,[3565]
sub bx,0xcc
mov [bx],0CCh

解决方案

NASM can't figure out what you meant by a line like mov [bx],0CCh. Clearly, this sets something to 0CCh. But do you want to have bx pointing to a single byte , short, long, ...? This will manifest itself as the fairly self-explanatory error: operation size not specified in NASM. You could avoid the error specifying the type, as shown below:

SECTION .text
    global start

start:
    add bx,[3565]
    sub bx,0xcc
    mov byte [bx],0CCh

That'd assemble it ok... of course, don't try to run it as it is, it'll produce EXCEPTION_ACCESS_VIOLATION. Just open it with a debugger and you'll understand why.

• 译文

 

我在emu8086中编写了这段代码，并且在模拟器中运行得很好，但是当我尝试使用NASM进行编译时，它抛出了错误消息："未指定操作大小"，请帮助某人？

 添加bx，[3565] 
 sub bx，0xcc 
 mov [bx]，0CCh 
  

解决方案

 

NASM无法弄清这样的行是什么意思mov [bx]，0CCh 。显然，
会将值设置为0CCh。但是，是否要让bx指向单个字节
，short，long，...？这将表现为非常明显的
错误：未在NASM中指定操作大小。您可以避免指定类型的错误，如下所示：

  SECTION .text 
全局开始
 
开始：
加bx，[3565] 
子bx，0xcc 
移动字节[bx]，0CCh 
  

可以正常组装了……当然，不要尝试按原样运行它，它会产生 EXCEPTION_ACCESS_VIOLATION 。只需使用调试器打开它，您就会明白为什么。