The Cortex-M3 processor implements a local exclusive monitor. For more information about semaphores and the local exclusive monitor, see the ARMv7M ARM Architecture Reference Manual.

The local monitor within the processor has been constructed so that it does not hold any physical address, but instead treats any access as matching the address of the previous LDREX. This means that the implemented exclusives reservation granule is the entire memory address range.

The Cortex-M3 processor does not support exclusive accesses to bit-band regions.