80386 Programmer's Reference Manual -- Opcode STR

STR -- Store Task Register

OpcodeInstructionClocks DescriptionExample
0F 00 /1strw r/m16pm=23/27 Load EA word into task registerstrw %cx
strw (%ebx,1)
strw (%ebx,2)
strw (%ebx,%ebp,1)


r/m := task register;


The contents of the task register are copied to the two-byte register or memory location indicated by the effective address operand.

STR is used only in operating system software. It is not used in application programs.

Flags Affected


Protected Mode Exceptions

#GP(0) if the result is in a nonwritable segment; #GP(0) for an illegal memory operand effective address in the CS, DS, ES, FS, or GS segments; #SS(0) for an illegal address in the SS segment; #PF(fault-code) for a page fault

Real Address Mode Exceptions

Interrupt 6; STR is not recognized in Real Address Mode

Virtual 8086 Mode Exceptions

Same exceptions as in Real Address Mode


The operand-size attribute has no effect on this instruction.

[Home Page dell'ITIS "Fermi"] [80386 Programmer's Reference Manual Index] [Previous] [Next]