4.2.13. CLREX

CLeaR EXclusive. Clears the local record of the executing processor that an address has had a request for an exclusive access.

Syntax

CLREX{cond}

where:

cond

is an optional condition code (see Conditional execution).

Note

This is an unconditional instruction in ARM. cond is only allowed in Thumb-2 code, using a preceding IT instruction.

Usage

Use the CLREX instruction to return a closely-coupled exclusive access monitor to its open-access state. This removes the req uirement for a dummy store to memory. See ARM Architecture reference Manual for more information on synchronization primitive support.

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 ARM instruction is available in ARMv6T2 and above.

This 32-bit Thumb-2 instruction is available in T2 variants of ARMv6 and above.

There is no 16-bit Thumb CLREX instruction.

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