Patent ID: 6385718
Filing Date: 2002-05-07
Classification: G06F

Abstract:
In a method of operating a computer system including a microprocessor which operates in a virtual operating mode that allows an existing program previously written for an earlier microprocessor to execute in a protected, paged, multi-tasking environment under a host operating software program, said host operating software program having emulation software for emulating the way interrupt (INTn) instructions in said existing program would have been executed by said earlier microprocessor, said method comprising:(a) providing a user programmable mode bit map resident in said host operating software program, said mode bit map including a series of mode bits corresponding to said INTn instructions, said mode bits designating at least one of an emulating first state and a non-emulating second state, wherein a selection to emulate an instruction or to execute an instruction without emulation is based on a period time consumed to emulate a respective instruction; (b) if said INTn instruction designates said emulating first state, then executing said INTn instruction using said emulation software; and (c) if said INTn instruction designates said non-emulating second state, then executing said INTn instruction without emulation via said existing program previously written.