This is a hint instruction. It is optional whether this instruction
is implemented or not. If this instruction is not implemented, it
executes as a
NOP. The assembler produces a diagnostic message
if the instruction executes as a
NOP on the target.
YIELD executes as a
YIELD indicates to the hardware that the current
thread is performing a task, for example a spinlock, that can be
swapped out. Hardware can use this hint to suspend and resume threads
in a multithreading system.