Hex/Dec conversion

0x 400 => 1K
0x 1000 => 4K
0x 8000 => 32K
0x 2 0000 ==> 128K
0x 4 0000 ==> 256K
0x 8 0000 ==> 512K
0x 10 0000 ==> 1M
0x 1000 0000 ==> 256M
0x 4000 0000 ==> 1G
0x 8000 0000 ==> 2G
0x c000 0000 ==> 3G
0x 1 0000 0000 (0x ffff ffff) ==> 4G