Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

4-342 Vol. 2B
INSTRUCTION SET REFERENCE, N-Z
Real-Address Mode Exceptions
#UD The STR instruction is not recognized in real-address mode.
Virtual-8086 Mode Exceptions
#UD The STR instruction is not recognized in virtual-8086 mode.
Compatibility Mode Exceptions
Same exceptions as in Protected Mode.
64-Bit Mode Exceptions
#GP(0) If the memory address is in a non-canonical form.
#SS(U) If the stack address is in a non-canonical form.
#PF(fault-code) If a page fault occurs.
#AC(0) If alignment checking is enabled and an unaligned memory
reference is made while the current privilege level is 3.