13.26 CLREX

Clear Exclusive.

Syntax

CLREX{cond}

where:

cond

is an optional condition code.

Note:

cond is permitted only in T32 code, using a preceding IT instruction, but this is deprecated in Arm®v8. This is an unconditional instruction in A32.

Usage

Use the CLREX instruction to clear the local record of the executing processor that an address has had a request for an exclusive access.

CLREX returns a closely-coupled exclusive access monitor to its open-access state. This removes the requirement for a dummy store to memory.

It is implementation defined whether CLREX also clears the global record of the executing processor that an address has had a request for an exclusive access.

Architectures

This 32-bit instruction is available in A32 and T32.

There is no 16-bit CLREX instruction in T32.

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