x86 Instruction Set Reference

STR

Store Task Register

Opcode	Mnemonic	Description
`0F 00 /1`	`STR r/m16`	Stores segment selector from TR in r/m16.

Description
Stores the segment selector from the task register (TR) in the destination operand. The destination operand can be a general-purpose register or a memory location. The segment selector stored with this instruction points to the task state segment (TSS) for the currently running task. When the destination operand is a 32-bit register, the 16-bit segment selector is copied into the lower 16 bits of the register and the upper 16 bits of the register are cleared. When the destination operand is a memory location, the segment selector is written to memory as a 16-bit quantity, regardless of operand size. The STR instruction is useful only in operating-system software. It can only be executed in protected mode.

Description

Stores the segment selector from the task register (TR) in the destination operand. The destination operand can be a general-purpose register or a memory location. The segment selector stored with this instruction points to the task state segment (TSS) for the currently running task.

When the destination operand is a 32-bit register, the 16-bit segment selector is copied into the lower 16 bits of the register and the upper 16 bits of the register are cleared. When the destination operand is a memory location, the segment selector is written to memory as a 16-bit quantity, regardless of operand size.

The STR instruction is useful only in operating-system software. It can only be executed in protected mode.

Operation
Destination = TR.SegmentSelector;

Flags affected
None.