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

Convert links to hugo format and insert more breaks

Browse Source
This commit is contained in:
Philipp Oppermann
2016-04-25 21:57:21 +02:00
parent cdc0b0748b
commit 7b2bdf5c3c
7 changed files with 43 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
blog/post/2015-08-25-entering-longmode.md
View File

@@ -10,12 +10,15 @@ aliases = [
In the [previous post] we created a minimal multiboot kernel. It just prints `OK` and hangs. The goal is to extend it and call 64-bit [Rust] code. But the CPU is currently in [protected mode] and allows only 32-bit instructions and up to 4GiB memory. So we need to set up _Paging_ and switch to the 64-bit [long mode] first.
I tried to explain everything in detail and to keep the code as simple as possible. If you have any questions, suggestions, or issues, please leave a comment or [create an issue] on Github. The source code is available in a [repository][source code], too.
[previous post]: {{ page.previous.url }}
[previous post]: {{% relref "2015-08-18-multiboot-kernel.md" %}}
[Rust]: http://www.rust-lang.org/
[protected mode]: https://en.wikipedia.org/wiki/Protected_mode
[long mode]: https://en.wikipedia.org/wiki/Long_mode
<!--more-->
I tried to explain everything in detail and to keep the code as simple as possible. If you have any questions, suggestions, or issues, please leave a comment or [create an issue] on Github. The source code is available in a [repository][source code], too.
[create an issue]: https://github.com/phil-opp/blog_os/issues
[source code]: https://github.com/phil-opp/blog_os/tree/entering_longmode/src/arch/x86_64
@@ -38,7 +41,7 @@ error:
At address `0xb8000` begins the so-called [VGA text buffer]. It's an array of screen characters that are displayed by the graphics card. A [future post] will cover the VGA buffer in detail and create a Rust interface to it. But for now, manual bit-fiddling is the easiest option.
[VGA text buffer]: https://en.wikipedia.org/wiki/VGA-compatible_text_mode
[future post]: {{ page.next.next.url }}
[future post]: {{% relref "2015-10-23-printing-to-screen.md" %}}
A screen character consists of a 8 bit color code and a 8 bit [ASCII] character. We used the color code `4f` for all characters, which means white text on red background. `0x52` is an ASCII `R`, `0x45` is an `E`, `0x3a` is a `:`, and `0x20` is a space. The second space is overwritten by the given ASCII byte. Finally the CPU is stopped with the `hlt` instruction.
@@ -530,4 +533,4 @@ It's time to finally leave assembly behind[^leave_assembly_behind] and switch to
[^leave_assembly_behind]: Actually we will still need some assembly in the future, but I'll try to minimize it.
[Rust]: https://www.rust-lang.org/
[next post]: {{ page.next.url }}
[next post]: {{% relref "2015-09-02-set-up-rust.md" %}}