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Few misspellings fixed

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Daniel Alejandro Campoverde Carrión [alx741] 2015-01-20 11:38:32 -05:00
parent 731ca87574
commit 0024b563e7
1 changed files with 2 additions and 2 deletions
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linux-bootstrap-2.md
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@ -29,7 +29,7 @@ And we can get physical address if we know these two parts by:
PhysicalAddress = Segment * 16 + Offset
```
Memory segmentation was completely remade in the protected mode. There are no 64 kilobytes fixed-size segments. All memory segments described by `Global Descriptor Table` (GDT) instead segment registers. GDT is a structure contained in memory. There is no fixed place for it in memory, but its address is stored in the special register - `GDTR`. Later, when we will see the GDT loading in the linux kernel code. There will be an operation for loading it in memory, something like:
Memory segmentation was completely redone in the protected mode. There are no 64 kilobytes fixed-size segments. All memory segments described by `Global Descriptor Table` (GDT) instead segment registers. GDT is a structure which contains in memory. There is no fixed place for it in memory, but its address is stored in the special register - `GDTR`. Later, when we will see the GDT loading in the linux kernel code. There will be an operation for loading it in memory, something like:
```assembly
lgdt gdt
@ -92,7 +92,7 @@ Don't worry, i know that it looks little scary after real mode, but it's easy. L
| 15 1 1 1 1 | Code | Execute/Read, conforming, accessed
```
As we can see first bit is 0 for data segment and 1 for code segment. Next three bits `EWA` are expansion direction (expand-dow segment will grow down, you can read more about this in [here](http://www.sudleyplace.com/dpmione/expanddown.html)), write enable and accessed for data segments. `CRA` bits are conforming (A transfer of execution into a more-privileged conforming segment allows execution to continue at the current privilege level), read enable and accessed.
As we can see first bit is 0 for data segment and 1 for code segment. Next three bits `EWA` are expansion direction (expand-dow segment will grow down, you can read more about this [here](http://www.sudleyplace.com/dpmione/expanddown.html)), write enable and accessed for data segments. `CRA` bits are conforming (A transfer of execution into a more-privileged conforming segment allows execution to continue at the current privilege level), read enable and accessed.
4. DPL (descriptor privilege level) defines the privilege level of the segment. I can be 0-3 where 0 is the most privileged.