1. A method for operating a computer processor comprising a first processor chip and a second processor chip connected in a stacked configuration, wherein the first and second processor chips each comprise one or more processors, the method comprising: selectively generating one of a plurality of control signals to operate the computer processor in one of a plurality of operating modes to control power of the computer processor, wherein selectively generating one of a plurality of control signals comprises: generating a first control signal to operate the computer processor in a first mode wherein the first processor chip is turned on and the second processor chip is turned off; and generating a second control signal to operate the computer processor in a second mode wherein both the first and second processor chips are turned on.