读书笔记： Programming in Lua, 4th Edition.
Bitwise Operators
> string.format("%x", 0xff & 0xabcd) --> cd
> string.format("%x", 0xff | 0xabcd) --> abff
> string.format("%x", 0xaaaa ~ -1) --> ffffffffffff5555
> string.format("%x", ~0) --> ffffffffffffffff
Negative displacements shift in the other direction, that is, a » n is the same as a « -n:
> string.format("%x", 0xff << 12) --> ff000
> string.format("%x", 0xff >> -12) --> ff000
If the displacement is equal to or larger than the number of bits in the integer representation (64 in Standard Lua, 32 in Small Lua), the result is zero, as all bits are shifted out of the result:
> string.format("%x", -1 << 80) --> 0
