Intel 64 and IA-32 | Atomic operations including acquire / release semantic

Question

According to the Intel 64 and IA-32 Architectures Software Developer\'s Manual the LOCK Signal Prefix \"ensures that the processor has exclusive use of any shared memory whi

Answer 1

No. From the IA32 manuals (Volume 3A, Chapter 8.2: Memory Ordering):

Reads or writes cannot be reordered with I/O instructions, locked instructions, or serializing instructions.

Therefore, a fence instruction is not needed with locked instructions.