michaelkuc6/blog_os
1
0
Fork 0
mirror of https://github.com/phil-opp/blog_os.git synced 2025-12-16 22:37:49 +00:00
Code Issues Projects Releases Wiki Activity

Fix lot of dead links in both the 2nd and 1st edition

Browse Source
This commit is contained in:
Philipp Oppermann
2019-07-07 10:33:12 +02:00
parent 265f9f9bd5
commit bc5631d9a8
30 changed files with 146 additions and 153 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
blog/content/first-edition/posts/02-entering-longmode/index.md
View File

@@ -410,9 +410,7 @@ gdt64:
dq 0 ; zero entry
dq (1<<43) | (1<<44) | (1<<47) | (1<<53) ; code segment
```
We chose the `.rodata` section here because it's initialized read-only data. The `dq` command stands for `define quad` and outputs a 64-bit constant (similar to `dw` and `dd`). And the `(1<<43)` is a [bit shift] that sets bit 43.
[bit shift]: http://www.cs.umd.edu/class/sum2003/cmsc311/Notes/BitOp/bitshift.html
We chose the `.rodata` section here because it's initialized read-only data. The `dq` command stands for `define quad` and outputs a 64-bit constant (similar to `dw` and `dd`). And the `(1<<43)` is a bit shift that sets bit 43.
### Loading the GDT
To load our new 64-bit GDT, we have to tell the CPU its address and length. We do this by passing the memory location of a special pointer structure to the `lgdt` (load GDT) instruction. The pointer structure looks like this: