SWPAH, SWPALH, SWPH, SWPLH
Swap halfword in memory.
Xn|SP] ; Acquire general registers
Xn|SP] ; Acquire and release general registers
Xn|SP] ; No memory ordering general registers
Xn|SP] ; Release general registers
- Is the 32-bit name of the general-purpose register to be stored.
- 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.
Supported in ARMv8.1 and later.
Swap halfword in memory atomically loads a 16-bit halfword from a memory location, and stores the value held in a register back to the same memory location. The value initially loaded from memory is returned in the destination register.
- If the destination register is not
SWPALHload from memory with acquire semantics.
SWPALHstore to memory with release semantics.
SWPHhas no memory ordering requirements.
For more information about memory ordering semantics see Load-Acquire, Store-Release in the ARMv8-A Architecture Reference Manual.
For information about memory accesses see Load/Store addressing modes in the ARMv8-A Architecture Reference Manual.