arno/linux-insides
1
0
Fork 0
mirror of https://github.com/0xAX/linux-insides.git synced 2024-11-05 23:09:38 +00:00
Code Issues Releases Wiki Activity

Merge branch 'AndrewRussellHayes-typo-fix'

Browse Source
This commit is contained in:
Alexander Kuleshov 2016-10-29 23:32:43 +06:00
commit 9db9f8d509
2 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Booting/linux-bootstrap-1.md
View File

@ -34,7 +34,7 @@ CS selector 0xf000
CS base 0xffff0000
```
The processor starts working in [real mode](https://en.wikipedia.org/wiki/Real_mode). Let's back up a little and try to understand memory segmentation in this mode. Real mode is supported on all x86-compatible processors, from the [8086](https://en.wikipedia.org/wiki/Intel_8086) all the way to the modern Intel 64-bit CPUs. The 8086 processor has a 20-bit address bus, which means that it could work with a 0-0x100000 address space (1 megabyte). But it only has 16-bit registers, which hace a maximum address of 2^16 - 1 or 0xffff (64 kilobytes). [Memory segmentation](http://en.wikipedia.org/wiki/Memory_segmentation) is used to make use of all the address space available. All memory is divided into small, fixed-size segments of 65536 bytes (64 KB). Since we cannot address memory above 64 KB with 16 bit registers, an alternate method is devised. An address consists of two parts: a segment selector, which has a base address, and an offset from this base address. In real mode, the associated base address of a segment selector is `Segment Selector * 16`. Thus, to get a physical address in memory, we need to multiply the segment selector part by 16 and add the offset:
The processor starts working in [real mode](https://en.wikipedia.org/wiki/Real_mode). Let's back up a little and try to understand memory segmentation in this mode. Real mode is supported on all x86-compatible processors, from the [8086](https://en.wikipedia.org/wiki/Intel_8086) all the way to the modern Intel 64-bit CPUs. The 8086 processor has a 20-bit address bus, which means that it could work with a 0-0x100000 address space (1 megabyte). But it only has 16-bit registers, which have a maximum address of 2^16 - 1 or 0xffff (64 kilobytes). [Memory segmentation](http://en.wikipedia.org/wiki/Memory_segmentation) is used to make use of all the address space available. All memory is divided into small, fixed-size segments of 65536 bytes (64 KB). Since we cannot address memory above 64 KB with 16 bit registers, an alternate method is devised. An address consists of two parts: a segment selector, which has a base address, and an offset from this base address. In real mode, the associated base address of a segment selector is `Segment Selector * 16`. Thus, to get a physical address in memory, we need to multiply the segment selector part by 16 and add the offset:
```
PhysicalAddress = Segment Selector * 16 + Offset

2
contributors.md
View File

@ -98,4 +98,4 @@ Thank you to all contributors:
* [Tim Konick](https://github.com/tijko)
* [Anastas Stoyanovsky](https://github.com/anastasds)
* [Faiz Halde](https://github.com/7coder7)
* [Andrew Hayes](https://github.com/AndrewRussellHayes)