RetOS

IMP NOTICE: THE MAKEFILE IS NOT FUNCTIONAL AND IS STILL IN DEVLOPEMENT!

RetOS is a hobby x86 operating system built from scratch using C and x86 Assembly. No libc. No hand-holding. GRUB, and raw VGA memory.

Built for learning OS development the hard (and fun) way.

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Features

• Boots using GRUB (BIOS)
• Custom 32-bit kernel
• VGA text mode driver
• Minimal printf implementation
• Clean project structure
• Runs on QEMU

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📁 Project Structure

RetOS/ ├── boot/ │ └── grub/ │ └── grub.cfg ├── kernel/ │ ├── boot.asm │ ├── kernel.c │ ├── printf.c │ └── printf.h ├── build/ # generated (ignored) ├── iso/ # generated (ignored) └── README.md

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Building RetOS

Requirements

• nasm
• gcc (with multilib support)
• grub-pc-bin
• xorriso
• qemu-system-x86

Build kernel

nasm -f elf32 kernel/boot.asm -o build/boot.o
gcc -m32 -ffreestanding -c kernel/kernel.c -o build/kernel.o
gcc -m32 -ffreestanding -c kernel/printf.c -o build/printf.o
ld -m elf_i386 -T kernel/linker.ld -o build/kernel.bin \
   build/boot.o build/kernel.o build/printf.o