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80386 微处理器分段单元大小

[英]80386 Microprocessor Segmentation Unit Size

原文 2020-12-09 07:57:18 0 1 memory/ memory-management/ architecture/ microprocessors/ memory-segmentation

I'm learning 80386DX microprocessor with 32 bit data bus & 32 bit address bus.我正在学习具有 32 位数据总线和 32 位地址总线的 80386DX 微处理器。 80386 can have max 4GB physical memory & can have 16384 segments of 64KB each. 80386 可以有最大 4GB 物理 memory 并且可以有 16384 个 64KB 的段。 But most of the online & book resources say that any single segment can have any varying size ranging from 1Byte all the way to 4GB max.但是大多数在线和书籍资源说，任何单个段都可以有任何不同的大小，从 1Byte 一直到最大 4GB。

So how is it possible that 80386DX can have max 16384 segments in physical memory?那么 80386DX 怎么可能在物理 memory 中最多有 16384 个段？

If I keep 1GB as my segment size I'd have 4 segments in total, so if I keep my segments size 16KB, I should be able to have more than 16384 segments?如果我保持 1GB 作为我的段大小，我总共有 4 个段，所以如果我保持我的段大小为 16KB，我应该能够有超过 16384 个段？

1 个解决方案

What you refer is the Memory Management Unit which has two sub components which is Segmentation unit and Paging unit.您指的是 Memory 管理单元，它有两个子组件，即分段单元和分页单元。 If you refer to segmentation, you can get variable length segments of 64 Kbytes in size of each.如果您参考分段，您可以获得每个大小为 64 KB 的可变长度段。 Else you can refer to paging as size of 4GB units.否则，您可以将分页称为 4GB 单位的大小。 Anyways task on 80386 can have a maximum of 16,381 segments of up to 4GB each,无论如何，80386 上的任务最多可以有 16,381 个段，每个段最多 4GB，
thus providing 64 TB of virtual memory to each task从而为每个任务提供 64 TB 的虚拟 memory