Patent ID: 7421686

Claim:
A program storage medium storing an emulation system for executing a register-based program code written for a first computer on a second computer, wherein the first computer has a set of registers including at least one variable size register which is addressable by the program code in a plurality of different widths, the emulation system, when executed by the second computer, being operative to generate an intermediate representation of said program code by a process comprising the steps of: generating a plurality of register objects representing said registers of said first computer as referred to by the program code; representing the at least one variably sized register of said first computer by an associated set of said register objects, one register object being provided for each width of the variably sized register as referred to by the program code; and wherein said process comprises the further step of generating expression objects, each representing a different operator or operand of the program code as that element arises in the program code, each expression object being referenced by a register object to which it relates either directly, or indirectly via references from other expression objects.