Method of using a target processor to execute programs of a source

Abstract

A method of utilizing large virtual addressing in a target computer to implement an instruction set translator (1ST) for dynamically translating the machine language instructions of an alien source computer into a set of functionally equivalent target computer machine language instructions, providing in the target machine, an execution environment for source machine operating systems, application subsystems, and applications. The target system provides a unique pointer table in target virtual address space that connects each source program instruction in the multiple source virtual address spaces to a target instruction translation which emulates the function of that source instruction in the target system. The target system efficiently stores the translated executable source programs by actually storing only one copy of any source program, regardless of the number of source address spaces in which the source program exists. The target system efficiently manages dynamic changes in the source machine storage, accommodating the nature of a preemptive, multitasking source operating system. The target system preserves the security and data integrity for the source programs on a par with their security and data integrity obtainable when executing in source processors (i.e. having the source architecture as their native architecture). The target computer execution maintains source-architected logical separations between programs and data executing in different source address spaces--without a need for the target system to be aware of the source virtual address spaces.