1 vbits=0x00000000 ctz(0x00000000)=32 2 vbits=0x00000000 ctz(0x00000001)=0 3 vbits=0x00000040 ctz(0x00000090)=4 4 vbits=0x00000a00 ctz(0x00000500)=8 5 vbits=0x001e0000 ctz(0x000f0000)=16 6 vbits=0xfffffffe ctz(0xffffffff)=0 7
