Let's assume that the kernel assigns the linear address space between 0x20000000 and 0x2003ffff to a running process. This space consists of exactly 64 pages. 1page=4KB 64pages=64*4KB=2^6*2^2*2

16进制（1，2，3，4，5，6，7，8，9，a，b，c，d，e，f），一个地址表示一个Byte，即8bit 0x80000000 33221100 77665544 bbaa9988 ffeeddcc  0x80000010 76543210 ... 0x80000000   00000000 0x80000001 00001100 0x80000002 00220000 0