Quick Question on ARM

Hi All,
do ARM have any instruction to halt processor? I'm writting for the application which gonna be interrup driven so I don't want to put wasting cycles (I assume that it will be power eater)into the main function.
do ARM have any instruction to halt processor? I'm writting for the application which gonna be interrup driven so I don't want to put wasting cycles (I assume that it will be power eater)into the main function.