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Uncapitalize BITS for consistency (and move it after section)

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Philipp Oppermann
2015-08-10 13:07:52 +02:00
parent e38f3cfe52
commit 2e0fa08605
1 changed files with 2 additions and 2 deletions
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4
_posts/2015-07-22-rust-os-boot.md
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@@ -82,8 +82,8 @@ To boot our kernel, we must add some code that the bootloader can call. Let's cr
```nasm ```nasm
global start global start
BITS 32
section .text section .text
bits 32
start: start:
mov dword [0xb8000], 0x2f4b2f4f mov dword [0xb8000], 0x2f4b2f4f
hlt hlt
@@ -91,8 +91,8 @@ start:
There are some new commands: There are some new commands:
- `global` exports a label (makes it public). As `start` will be the entry point of our kernel, it needs to be public. - `global` exports a label (makes it public). As `start` will be the entry point of our kernel, it needs to be public.
- `BITS 32` specifies that the following lines are 32-bit instructions. It's needed because the CPU is still in [Protected mode] when GRUB starts our kernel. When we switch to [Long mode] in the [next post] we can use `BITS 64` (64-bit instructions).
- the `.text` section is the default section for executable code - the `.text` section is the default section for executable code
- `bits 32` specifies that the following lines are 32-bit instructions. It's needed because the CPU is still in [Protected mode] when GRUB starts our kernel. When we switch to [Long mode] in the [next post] we can use `bits 64` (64-bit instructions).
- the `mov dword` instruction moves the 32bit constant `0x2f4f2f4b` to the memory at address `b8000` (it writes `OK` to the screen, an explanation follows in the [next post]) - the `mov dword` instruction moves the 32bit constant `0x2f4f2f4b` to the memory at address `b8000` (it writes `OK` to the screen, an explanation follows in the [next post])
- `hlt` is the halt instruction and causes the CPU to stop - `hlt` is the halt instruction and causes the CPU to stop