17.18 LDAXRH

Load-Acquire Exclusive Register Halfword.

Syntax

LDAXRH Wt, [Xn|SP{,#0}]

Where:

Wt
Is the 32-bit name of the general-purpose register to be transferred.
Xn|SP
Is the 64-bit name of the general-purpose base register or stack pointer.

Usage

Load-Acquire Exclusive Register Halfword derives an address from a base register value, loads a halfword from memory, zero-extends it and writes it to a register. The memory access is atomic. The PE marks the physical address being accessed as an exclusive access. This exclusive access mark is checked by Store Exclusive instructions. See Synchronization and semaphores in the Arm® Architecture Reference Manual Arm®v8, for Arm®v8‑A architecture profile. The instruction also has memory ordering semantics as described in Load-Acquire, Store-Release in the Arm® Architecture Reference Manual Arm®v8, for Arm®v8‑A architecture profile. For information about memory accesses see Load/Store addressing modes in the Arm® Architecture Reference Manual Arm®v8, for Arm®v8‑A architecture profile.

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