files/cookie

#define BITCOUNT(x)	(((BX_(x)+(BX_(x)>>4)) & 0x0F0F0F0F) % 255)
#define  BX_(x)		((x) - (((x)>>1)&0x77777777)			\
			     - (((x)>>2)&0x33333333)			\
			     - (((x)>>3)&0x11111111))

		-- really weird C code to count the number of bits in a word