Contains two modifications to improve ASIC resistance: shuffle and integer math.
Shuffle makes use of the whole 64-byte cache line instead of 16 bytes only, making Cryptonight 4 times more demanding for memory bandwidth.
Integer math adds 64:32 bit integer division followed by 64 bit integer square root, adding large and unavoidable computational latency to the main loop.
More details and performance numbers: https://github.com/SChernykh/xmr-stak-cpu/blob/master/README.md
Lee Clagett