Hobby Operating System to run PONG(C, x86 Assembly)

• This project is a hobby game-oriented OS capable of running a custom implemetation of PONG without relying on any external operating system.
• The system is being developed incrementally, starting in text mode to stabilize hardware interaction before introducing graphical complexity.

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Current State

• Executes a custom bootloader
• Switches to 32-bit protected mode
• Initializes VGA text-mode output (written to memory at 0xB8000)
• Initializes a PS/2 keyboard driver (polling-based)
• Displays a terminal interface with a shell prompt
• Supports a minimal interactive shell.
• The kernel currently runs entirely in text mode.

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Implemented Features

Boot & Architecture

• Custom bootloader written in x86 assembly
• 32-bit protected-mode kernel
• Cross-compiled using an i686-elf GCC toolchain
• Bootable ISO image tested with QEMU

Drivers

VGA text-mode driver with:

• Character output
• Line wrapping
• Screen clearing
• Scrolling support

PS/2 keyboard driver using controller polling

• Backspace handling
• Input buffering

Terminal & Shell

• Interactive terminal interface
• Input buffer with length tracking
• Backspace editing support

Built-in commands:

• help
• clear
• echo
• shutdown (QEMU ACPI poweroff: port I/O 0x604)

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Shell Architecture

• Commands will later be mapped to handler functions via a structured command table, allowing scalable and modular command extension.

Architecture Overview

Bootloader (Assembly)
↓
Switch to Protected Mode
↓
Kernel (C)
├── VGA Driver
├── PS/2 Keyboard Driver (Polling)
├── Terminal Interface
└── Shell Command Dispatcher (later)

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Development Environment

• Cross-Compiler :The project uses a freestanding cross-compiler toolchain targeting i686-elf.
• OSDev Wiki: GCC Cross-Compiler

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Primary references:

• Interrupts – OSDev Wiki

• PS/2 Keyboard – OSDev Wiki

• The Little Book about OS Development

• Creating a Shell

• Emulator: Tested primarily using QEMU (i386)

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Build & Run

• Build: make
• Run: qemu-system-i386 -cdrom os.iso OR make run

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Goals

Short-Term

• Transition keyboard driver from polling to IRQ-based handling
• Implement PIT timer support
• Improve shell command parsing and modularization

Mid-Term

• Switch from text mode to a graphics mode (VGA or VESA)
• Implement a basic framebuffer abstraction
• Develop game loop timing infrastructure

Long-Term

• Implement PONG entirely within the kernel environment
• Add minimal file system abstraction
• Explore basic task or module separation

This project is primarily an exploration of:

• direct hardware interaction via port I/O and memory-mapped VGA
• interrupt handling
• freestanding C development
• validation under QEMU and x86 boot media

It is intentionally built without relying on external OS libraries or hosted runtime environments.

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Status

The project is in the early kernel phase and focused on building stable infrastructure before implementing graphical game logic.