位反转的最佳算法（C语言实现）

Reversing the bits in an integer x is somewhat painful, but here's a SWAR algorithm for a 32-bit value:

unsigned int
reverse(register unsigned int x)
{
	x = (((x & 0xaaaaaaaa) >> 1) | ((x & 0x55555555) << 1));
	x = (((x & 0xcccccccc) >> 2) | ((x & 0x33333333) << 2));
	x = (((x & 0xf0f0f0f0) >> 4) | ((x & 0x0f0f0f0f) << 4));
	x = (((x & 0xff00ff00) >> 8) | ((x & 0x00ff00ff) << 8));
	return((x >> 16) | (x << 16));

}