The present invention provides a data processing apparatus and method for
testing power management instructions. The data processing apparatus
comprises a processor for executing data processing instructions including
power management instructions, at least one of the power management
instructions being a command power management instruction. A power
management controller is also provided for receiving command data from the
processor when a command power management instruction is executed by the
processor, and to control power management logic to perform an associated
set of power management functions dependent on the command data. The data
processing apparatus includes first power management logic controllable by
the power management controller, with the power management controller also
having an interface to enable communication with additional power
management logic. In accordance with the present invention, the processor
is arranged when executing the command power management instruction to
specify within the command data provided to the power management
controller whether an emulation mode of operation is set. The power
management controller is arranged when the emulation mode is not set to
initiate the associated set of power management functions dependent on the
command data, whilst if the emulation mode is set it is arranged to only
initiate a subset of the associated set of power management functions not
requiring communication over the interface. By this approach, it is
possible to perform some testing of power management software before all
aspects of the power management hardware have been designed.
