arcbbb

$ g++ count_bits.cpp  -o count_bits -std=c++0x -O3 && ./count_bits
count_directly        : sum=7998296000, duration=5202343000 ns
count_by_table        : sum=7998296000, duration=3551468000 ns
count_by_table8       : sum=7998296000, duration=2642850000 ns
count_by_table8_unroll: sum=7998296000, duration=2241039000 ns
count_by_bit_operation: sum=7998296000, duration=1354588000 ns
Illegal instruction (core dumped)