MOS 6502 Emulator

MOS 6502 CPU Emulator

MOS 6502 emulator running in WebAssembly.

This is a MOS 6502 CPU emulator, written in C and compiled into WebAssembly. The MOS 6502 microprocessor is an 8-bit microprocessor that was widely used in the 1980s. It was used in many home computers and video game consoles, such as the Commodore 64, Atari 2600, Nintendo Entertainment System and the Apple II.

CPU is currently executing Klaus' functional test program in your browser. The program verifies the functionality of all the opcodes of the 6502 CPU and requires approximately 96 million cycles to complete, and is an important test for ensuring that the emulator is working correctly.

Note that the emulation may appear slow, but this is due to the time required to output CPU and register information. While this information can be useful for debugging purposes, it can significantly impact the performance of the emulator. Without these debugging functions, the test completes in under 250 milliseconds on a modern x86 machine.

The emulator's graphical user interface is powered by the Nuklear immediate mode GUI library with SDL backend.

Why?

As a technology enthusiasts, it is fun and interesting to explore the history of computing and experience how software ran on vintage hardware.

How?

To use the emulator, simply close this window and press the green "Continue" button. The emulator will then begin executing the test program and you can observe the results in real time.