0F 01 /0                 SGDT m                 Store GDTR to m

0F 01 /1                 SIDT m                 Store IDTR to m


Description

Stores the contents of the global descriptor table register (GDTR) or the interrupt descriptor table register (IDTR) in the destination operand. The destination operand specifies a 6-byte memory location. If the operand-size attribute is 32 bits, the 16-bit limit field of the register is stored in the lower 2 bytes of the memory location and the 32-bit base address is stored in the upper 4 bytes. If the operand-size attribute is 16 bits, the limit is stored in the lower 2 bytes and the 24-bit base address is stored in the third, fourth, and fifth byte, with the sixth byte filled with 0s.


The SGDT and SIDT instructions are only useful in operating-system software; however, they can be used in application programs without causing an exception to be generated.


See "LGDT/LIDT—Load Global/Interrupt Descriptor Table Register" in this chapter for information on loading the GDTR and IDTR.


Operands        Bytes                Clocks

mem48                5                4   NP


Flags

None.

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