A simple 64-bit operating system built from scratch for x86-64 architectures, featuring a custom bootloader, kernel, and shell.

• Custom Bootloader: Transitions the CPU from 16-bit real mode to 64-bit long mode.
• Monolithic Kernel: Includes drivers, memory management, and a scheduler.
• Memory Management: Paging, physical memory management (PMM), and a kernel heap (kmalloc/kfree).
• Interrupt Handling: Manages both CPU exceptions and hardware interrupts (IRQs).
• Drivers: Supports VGA text mode, keyboard, RTC, and serial communication.
• Simple Scheduler: A round-robin scheduler for cooperative multitasking (The kernel runs a real-time clock task in the bottom right of the screen and a rotation animation task in the top right).
• Interactive Shell: A basic command-line interface with commands like help, time, and memorymap.

• NASM (Assembler)
• Clang (C Compiler)
• lld (Linker)
• QEMU (Emulator)

To build the operating system, run the build.sh script. This will compile the bootloader and kernel and create a disk image named tinyos.img.

./build.sh

To run the OS in QEMU, use the run.sh script.

./run.sh

This will launch QEMU with the tinyos.img disk image, and the serial port output will be redirected to your terminal.

The project is organized into two main parts: the bootloader and the kernel.

.
├── bootloader/       # 16, 32, and 64-bit assembly code for booting
├── kernel/           # C and assembly source for the 64-bit kernel
│   ├── inc/          # Header files for the kernel
│   └── src/          # Source files for the kernel
├── build.sh          # Build script
├── run.sh            # Script to run the OS in QEMU
└── linker.ld         # Linker script for memory layout

bootloader/: Contains all the assembly code responsible for the initial boot process, including switching to 64-bit long mode and loading the kernel.

kernel/: Contains the C and assembly source code for the main operating system kernel, including all drivers and core functionalities.