ARM Cortex-M4 - Dmb; Data Memory Barrier

The Cortex-M4 Instruction Set
ARM DUI 0553A Copyright © 2010 ARM. All rights reserved. 3-160
ID121610 Non-Confidential
3.12.3 DMB
Data Memory Barrier.
Syntax
DMB{cond}
where:
cond Is an optional condition code, see Conditional execution on page 3-18.
Operation
DMB acts as a data memory barrier. It ensures that all explicit memory accesses that appear, in
program order, before the
DMB instruction are completed before any explicit memory accesses
that appear, in program order, after the
DMB instruction. DMB does not affect the ordering or
execution of instructions that do not access memory.
Condition flags
This instruction does not change the flags.
Examples
DMB ; Data Memory Barrier