Patent ID: 6421635
Filing Date: 2002-07-16
Classification: G06F

Abstract:
An apparatus for managing at least one signal during an emulation of a system call, wherein an emulator is emulating an application to operate on an operating system, the operating system is resident on a computer system, the emulator includes a list identifying deferred signals, and the computer system includes a register through which the application and the operating system communicate, the apparatus comprising:a first check mechanism that sets a global flag which indicates that the emulator is commencing an interruptible system call, and reviews the list prior to completion of the emulation of the system call to determine whether the at least one signal is identified therein; a delivery mechanism which operates if the first check mechanism has determined that the at least one signal is on the list, the delivery mechanism delivers the at least one stored signal to the application prior to completion of the emulation of the system call; a state mechanism which sets a watch state in the register during the emulation of the system call, wherein the watch state indicates whether control has been transferred from the operating system to the emulator after processing the emulated system call; and a second check mechanism which reviews the watch state and the global flag upon an arrival of the at least one signal, wherein the delivery mechanism delivers the at least one signal to the application prior to completion of the emulation of the system call, if the watch state is present and the global flag is set.