Function f2

src/crypto/sha1.cpp:25–25

uint32_t inline f1(uint32_t b, uint32_t c, uint32_t d) { return d ^ (b & (c ^ d)); }
uint32_t inline f2(uint32_t b, uint32_t c, uint32_t d) { return b ^ c ^ d; }
uint32_t inline f3(uint32_t b, uint32_t c, uint32_t d) { return (b & c) | (d & (b | c)); }

uint32_t inline left(uint32_t x) { return (x << 1) | (x >> 31); }