13.46 LDA

Load-Acquire Register.

Note:

This instruction is supported only in Arm®v8.

Syntax

LDA{cond} Rt, [Rn]

LDAB{cond} Rt, [Rn]

LDAH{cond} Rt, [Rn]

where:

cond
is an optional condition code.
Rt
is the register to load.
Rn
is the register on which the memory address is based.

Operation

LDA loads data from memory. If any loads or stores appear after a load-acquire in program order, then all observers are guaranteed to observe the load-acquire before observing the loads and stores. Loads and stores appearing before a load-acquire are unaffected.

If a store-release follows a load-acquire, each observer is guaranteed to observe them in program order.

There is no requirement that a load-acquire be paired with a store-release.

Restrictions

The address specified must be naturally aligned, or an alignment fault is generated.

The PC must not be used for Rt or Rn.

Availability

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

There is no 16-bit version of this instruction.

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