readme.md

https://wiki.osdev.org/Bare_Bones#Booting_the_Operating_System

gcc cross compiler @ ~/opt/cross/ / i686-elf @ ~/opt/cross/i686-elf/bin/

Assemble boot.s

$ i686-elf-as boot.s -o boot.o

Compile the kernel

$ i686-elf-gcc -c kernel.c -o kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra

Linking the kernel

$ i686-elf-gcc -T linker.ld -o myos.bin -ffreestanding -O2 -nostdlib boot.o kernel.o -lgcc

To check whether grub could find the multiboot header in first 8KiB

$ grub-file --is-x86-multiboot myos.bin  # exits silently if passed, else $? set

To make cdrom image, first create dirs: isodir/boot/grub/ with kernel in boot/ and grub.cfg in boot/grub

$ grub-mkrescue -o myos.iso isodir

Boot the iso

$ qemu-system-i386 -cdrom myos.iso

Boot the kernel

$ qemu-system-i386 -kernel myos.bin

Keyboard Support

-> Need Interrupts -> Need Interrupt Descriptor Table -> Need Global Descriptor Table

Loading the GDT:

https://wiki.osdev.org/GDT_Tutorial

1. Paging is currently disabled
2. Assumed im non-flat (base != 0)
3. Hardcoded the gdt entries
4. Switched from AT&T to NASM