"The LGDT and SGDT instructions load and store the GDTR register, respectively."
"2.4.1 Global Descriptor Table Register (GDTR) 2.4.2 Local Descriptor Table Register (LDTR) 2.4.3 IDTR Interrupt Descriptor Table Register 2.4.4 Task Register (TR) On power up or reset of the processor, the base address is set to the default value of 0 and the limit is set to 0FFFFH."