x86502 is a 6502 processor emulator, completely written in x86 assembly.
It was written as an assignment for a course at the TU Delft, together with Maarten de Vries. The goal of the assignment was to write just such an emulator, with possibly some extra features if there was any time left.
As a extra feature we made it possible to run x86502 without an operating system. We wrote our own VGA and keyboard drivers and extended the emulator with a way to interface with those from the 6502 code. It is bootable directly from a bootloader like GRUB or LILO.
Apart from that, we also wrote a game in 6502 assembly to show the capabilities of the emulator.
At the start of the game:
While playing level 8:
The source code is published on Github: https://github.com/m-ou-se/x86502
The multiboot kernel image of x86502 with CopterGame can be downloaded here: https://github.com/m-ou-se/x86502/releases/download/v1/x86502
An image for a bootable floppy with x86502 and Coptergame can be found here: https://github.com/m-ou-se/x86502/releases/download/v1/x86502-floppy.img