什么是处理段和偏移量在实模式下的记忆？ [英] What are the segment and offset in real mode memory addressing?

问题描述

我读到内存寻址。我读到段偏移，然后描述符左右偏移。我知道如何在实模式计算出准确的地址。这一切都是好的，但我无法理解到底什么偏移？我到处都写着：

I am reading about memory addressing. I read about segment offset and then about descriptor offset. I know how to calculate the exact addresses in real mode. all this is ok, but I am unable to understand what exactly offset is?? Everywhere I read :

 In real mode, the registers are only 16 bits, so you can only address up to 64k.
 In order to allow addressing of more memory, addressקד are calculated from 
 segment * 16 + offset.

在这里，我可以理解的第一行。我们有16位，因此我们可以处理多达2 ^ 16 = 64K。
但什么是这第二行？什么段重新present？为什么我们用16乘以？为什么我们增加所抵消。我只是不明白这关集是什么？任何人都可以解释我或者给我链接，这个好吗？

Here I can understand the first line. We have 16 bits, so we can address up to 2^16 = 64k. but what is this second line? what the segment represent? why we multiply it with 16? why we add offset. I just can't understand what this off set is? Can anybody explain me or give me link for this please?

推荐答案

86下实模式内存的物理地址是20位长，并calcolated：

Under x86 Real-Mode Memory the physical address is 20 bit long and is calcolated:

PhysicalAddress = Segment * 16 + Offset

此外，还应检查：实模式内存管理

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