Patent ID: 7206884
Filing Date: 2007-04-17
Classification: G06F

Abstract:
1. Apparatus for processing data, said apparatus comprising: processing logic operable to perform processing operations under control of program instructions and subject to interruption by a plurality of interrupt events; and a nested interrupt controller operable to control nested execution of a plurality of active interrupt handling programs that are started and uncompleted and which is responsive to priorities associated with respective ones of said plurality of interrupt handling programs to control pre-emption of said plurality of active interrupt handling programs by a pending interrupt handling program; wherein: a priority of a given active interrupt handling program is alterable whilst said given active interrupt handling program is started and uncompleted such that a currently executing interrupt handling program does not have a highest priority of said plurality of active interrupt handling programs; and said nested interrupt controller is responsive to an interrupt event for a pending interrupt handling program: (i) to permit said pending interrupt handling program to pre-empt said plurality of active interrupt handling programs if a priority associated with said pending interrupt handling program is higher than a highest priority associated with any of said plurality of active interrupt programs as determined with respect to all of said plurality of active interrupt handling programs; and (ii) to prevent said pending interrupt handling program from pre-empting said plurality of active interrupt handling programs if said priority associated with said pending interrupt handling program is less than said highest priority associated with any of said plurality of active interrupt handling programs as determined with respect to all of said plurality of active interrupt handling programs.