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Remove striped output example

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Doesn't really add much value.
This commit is contained in:
Philipp Oppermann
2023-07-09 11:28:31 +02:00
parent c31f3c2728
commit 2676d69c31
3 changed files with 2 additions and 28 deletions
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24
blog/content/edition-3/posts/02-booting/index.md
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@@ -1104,30 +1104,6 @@ We see that our guess that the whole screen would turn gray was right:
We finally see some output from our little kernel!
You can try experimenting with the pixel bytes if you like, for example by increasing the pixel value on each loop iteration:
```rust ,hl_lines=5-9
// in src/kernel/main.rs
fn kernel_main(boot_info: &'static mut BootInfo) -> ! {
if let Some(framebuffer) = boot_info.framebuffer.as_mut() {
let mut value = 0x90;
for byte in framebuffer.buffer_mut() {
*byte = value;
value = value.wrapping_add(7);
}
}
loop {}
}
```
We use the [`wrapping_add`] method here because Rust panics on implicit integer overflow (at least in debug mode).
The result looks as follows:
[`wrapping_add`]: https://doc.rust-lang.org/std/primitive.u8.html#method.wrapping_add
![QEMU showing repeating gradient columns](qemu-wrapping-add.png)
### Booting on Real Hardware
To boot on real hardware, write either the `uefi.img` or the `bios.img` disk image to an USB thumb drive.

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blog/content/edition-3/posts/02-booting/qemu-wrapping-add.png
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6
blog/content/edition-3/posts/03-screen-output/index.md
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@@ -38,7 +38,7 @@ The complete source code for this post can be found in the [`post-3.3`][post bra
In the [previous post], we learned how to make our minimal kernel bootable.
Using the [`BootInfo`] provided by the bootloader, we were able to access a special memory region called the _[framebuffer]_, which controls the screen output.
We wrote some example code to display a gray stripe pattern:
We wrote some example code to display a gray background:
[previous post]: @/edition-3/posts/02-booting/index.md
[`BootInfo`]: https://docs.rs/bootloader_api/latest/bootloader_api/info/struct.BootInfo.html
@@ -48,10 +48,8 @@ We wrote some example code to display a gray stripe pattern:
fn kernel_main(boot_info: &'static mut BootInfo) -> ! {
if let Some(framebuffer) = boot_info.framebuffer.as_mut() {
let mut value = 0x90;
for byte in framebuffer.buffer_mut() {
*byte = value;
value = value.wrapping_add(7);
*byte = 0x90;
}
}
loop {}