"PTR"和"NEAR PTR"有什么区别? [英] What is the difference between “PTR” and “NEAR PTR”?

查看：171 发布时间：2020/5/6 9:10:10 assembly x86 masm

本文介绍了"PTR"和"NEAR PTR"有什么区别?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

我正在查找包含"NEAR PTR"的示例，但可以轻松地用"PTR"替换它们.使用"NEAR PTR"有什么好处吗?

I was looking up examples containing "NEAR PTR", but they were easily replaceable with "PTR". Is there any advantage for using "NEAR PTR"?

NEAR是16位过去的遗留物.假设您的代码是32位或64位，则它们是相同的.

NEAR is a legacy from 16-bit past. Assuming your code is 32-bit or 64-bit, they are the same.

这与内存段有关(Wikipedia链接至x86 32位并指向 64位).

This is about memory segments (Wikipedia link to x86 32-bit and to 64-bit).

在 LABEL语句中 PTR和NEAR PTR都只存储一个32/64位的内存地址，没有段.

In LABEL statement both PTR and NEAR PTR just store a 32/64 bit memory address without segment.

如果在64位MASM下编译下一个代码:

If compile next code under 64-bit MASM:

_DATA SEGMENT
    justPtr LABEL PTR db
    nearPtr LABEL NEAR PTR db

    justPtrSize dd SIZEOF justPtr
    nearPtrSize dd SIZEOF nearPtr
_DATA ENDS

并在Visual Studio调试器下检查大小:

and check under Visual Studio debugger the sizes:

?justPtrSize
8
?nearPtrSize
8

独立PTR占用8字节(64位)，与NEAR PTR相同.

Indeed PTR occupies 8-byte (64 bit), same way as NEAR PTR does.

这篇关于"PTR"和"NEAR PTR"有什么区别?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

查看全文