Delayed exception emulation method and system in a digital computer system

摘要

A digital computer system containing a regular exception processing processor and a control subsystem is provided. The regular exception processing processor performs arithmetic processing under the control of an instruction. A regular exception handling processor is constructed according to the regular exception handling model, in which, if an exception condition occurs in relation to an instruction, the exception condition is handled in relation to that instruction. The regular exception handling processor also includes a pending exception indicator with a pending exception indication state and a no pending exception indication state. The control system provides a set of instructions to a regular exception processing processor to facilitate emulation of at least one instruction from the emulation application of at least one instruction from the emulation program. The emulation program is configured to be handled by a delayed exception handling processor configured according to a delayed exception handling model wherein if an exception is detected during the processing of an instruction, the exception condition is handled with respect to the subsequent instruction. A series of commands provided by the control system during emulation of an emulation program instruction may include: (i) determining if the pending exception indicator is in a pending exception indication state, and if so, handling the pending exception, (Ii) performs a processing operation according to the emulation processing instruction, and (iii) if an exception condition is detected during the processing operation, the exception condition is notified to the subsequent emulation program instruction Controls the regular exception processing processor to call an exception handler according to the processor's commutation exception handling model to condition the pending exception indicator to a pending exception indication to be processed during processing operations on the processor.