Snake OS

A baremetal x86 "operating system" that only runs the popular game Snake.

Inspired by https://github.com/jdah/tetris-os

Running/Testing:

Requirements:

• qemu-system-i386
• nasm
• Cross compilation: GCC and binutils for i386-elf (gdb, gcc, ld, objcopy)

Instructions:

git clone https://github.com/HarishgunaS/snake-os.git

Replace the paths found in the Makefile with the correct paths for the installed tools listed above.

make run

Completed:

• Basic two stage bootloader (no multiboot support)
  • loads Global Descriptor Table
  • enters 32 bit protected mode
  • launches kernel
• Basic interrupt setup
  • Creates and loads simple IDT, masks proper IRQs in PIC
  • Basic ISRs for IRQ0 and IRQ1 (timer and keyboard interrupts)
• Naive preliminary device drivers
  • Keyboard driver (returns last keyboard input)
  • Timer driver (returns ticks since kernel launch, can sleep for given ticks)
  • Screen driver (drawing mode set using BIOS interrupts during boot, can draw pixels and squares at given coordinates using VGA memory)
• Memory management
  • Very basic heap using the first 0x2000 bytes of memory
• Snake gameplay
  • Basic moving square on screen controlled by WASD
  • Snake dies when it touches itself or the edge of the screen

Resources:

• most learning and general information from wiki.osdev.org
• bootloader instructions from http://www.cs.cmu.edu/~410-s07/p4/p4-boot.pdf
• prior knowledge from os-tutorial by cfenollosa