ref: d79c8496a265c3d71d0e5537471ffbb41fa33c24
dir: /sys/src/ape/lib/openssl/crypto/cast/asm/readme/
There is a ppro flag in cast-586 which turns on/off generation of pentium pro/II friendly code This flag makes the inner loop one cycle longer, but generates code that runs %30 faster on the pentium pro/II, while only %7 slower on the pentium. By default, this flag is on.