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

NASM：未指定操作大小 - IT屋-程序員軟件開發技術分享社區 (it1352.com)

2020-05-16   IT屋

 

百度翻譯此文    有道翻譯此文

 

 

• 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

解決方案

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.

• 譯文

 

我在emu8086中編寫了這段代碼，並且在模擬器中運行得很好，但是當我嘗試使用NASM進行編譯時，它拋出了錯誤消息："未指定操作大小"，請幫助某人？

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

解決方案

 

NASM無法弄清這樣的行是什么意思mov [bx]，0CCh 。顯然，
會將值設置為0CCh。但是，是否要讓bx指向單個字節
，short，long，...？這將表現為非常明顯的
錯誤：未在NASM中指定操作大小。您可以避免指定類型的錯誤，如下所示：

  SECTION .text 
全局開始
 
開始：
加bx，[3565] 
子bx，0xcc 
移動字節[bx]，0CCh 
  

可以正常組裝了……當然，不要嘗試按原樣運行它，它會產生 EXCEPTION_ACCESS_VIOLATION 。只需使用調試器打開它，您就會明白為什么。