Load-Acquire RCpc Register Byte.
- Is the 32-bit name of the general-purpose register to be loaded.
- Is the 64-bit name of the general-purpose base register or stack pointer.
This instruction is supported in architectures ARMv8.3-A and later. It is optionally supported in ARMv8.2-A with the RCpc extension.
Load-Acquire RCpc Register Byte derives an address from a base register value, loads a byte from the derived address in memory, zero-extends it and writes it to a register.
The instruction has memory ordering semantics as described in Load-Acquire, Store-Release in the ARMv8-A Architecture Reference Manual, except that:
- There is no ordering requirement, separate from the requirements of a Load-Acquirepc or a Store-Release, created by having a Store-Release followed by a Load-Acquirepc instruction.
- The reading of a value written by a Store-Release by a Load-Acquirepc instruction by the same observer does not make the write of the Store-Release globally observed.
This difference in memory ordering is not described in the pseudocode.
For information about memory accesses, see Load/Store addressing modes in the ARMv8-A Architecture Reference Manual.