
ADVANCED PROCESSORS—80286 TO PENTIUM 14-21
Figure 14.15 | GDT and GDTR
LimitBaseAttribute
D-8191
D-2
D-1
D-0
Global Descriptor Ta ble Register (GDTR)
The GDT contains the descriptors of the segments used in system programs – there
is only one GDT for the whole system. As such, there is no selector for the GDT. On
startup, the descriptor of the GDT will be loaded into the GDTR. Once this is set up, the
system can start running application tasks. Figure 14.15 shows the descriptor of a GDT
loaded into the GDTR. Note that the GDT can contain a maximum of 8192 descriptors
and the limit field indicates the size of the GDT (here, a maximum sized GDT is sho ...