descriptor

GDT

00 c0 9a 00
00 00 0f ff

base:  00000000
limit: 00fff -> (fff+1)*4K = 16M

c0
1100 0000
G:   1 limit以4K为单位
D/B: 1

9a
1001 1010
P:   1
DPL: 00
S:   1 代码段，数据段

LDT

LDT2

----------------------------------------

14 c0 fa 00 
00 00 00 02

base:  14000000
limit: 00002  (2+1)*4K = 12K

c0
1100 0000
G:   1 limit以4K为单位
D/B: 1

fa
1111 1010
P:   1
DPL: 11
S:   1 代码段，数据段

----------------------------------------

14 c0 f3 00
00 00 3f ff

base:  14000000
limit: 0 3f ff  (3fff+1)*4K = 0x4000 * 4k = 64M

c0
1100 0000
G:   1 limit以4K为单位
D/B: 1

f3
1111 0111
P:   1
DPL: 11
S:   1 代码段，数据段

----------------------------------------