BLAKE3 in 6502 assembly

BLAKE3 is a cryptographic hash function. The MOS 6502 is the classic 8-bit microprocessor that powered the Apple II, the Commodore 64, and the NES console. This implementation of BLAKE3 runs on Ben Eater's 6502 breadboard computer. Source code is in rom.s.

This program loops over the BLAKE3 test vectors and hashes each one. Then it hashes a couple more inputs, including the one shown in the photo above, 1 MB of all zeros. This is larger than the 6502's 64 KiB of addressable memory, and with a 1 MHz clock it takes 17.7 minutes. You can reproduce the same result with b3sum in the terminal:

$ head -c 1000000 /dev/zero | b3sum --length=8
c211bb2e5afbd0ef  -

You can also run this program in the terminal with make emulate. This requires Rust and Cargo. The emulator is based on the emulator_6502 Rust crate by Garett Cooper.