초록 ▼

An emulator allows subject code written for a subject processor having subject processor registers and condition code flags to run in a non-compatible computing environment. The emulator identifies and records parameters of instructions in the subject code that affect status of the subject condition

An emulator allows subject code written for a subject processor having subject processor registers and condition code flags to run in a non-compatible computing environment. The emulator identifies and records parameters of instructions in the subject code that affect status of the subject condition code flags. Then, when an instruction in the subject code is encountered, such as a branch or jump, that uses the flag status to make a decision, the flag status is resolved from the recorded instruction parameters. Advantageously, emulation overhead is substantially reduced.

대표청구항 ▼

What is claimed is: 1. Computer software resident on a tangible computer readable storage medium and operable when executed by a computer to perform program code conversion comprising the steps of:(a) establishing one or more abstract registers, each corresponding to a unique flag parameter (operand

What is claimed is: 1. Computer software resident on a tangible computer readable storage medium and operable when executed by a computer to perform program code conversion comprising the steps of:(a) establishing one or more abstract registers, each corresponding to a unique flag parameter (operand) used by a flag-affecting instruction which selectively modifies a flag;(b) generating an intermediate representation (IR) tree for a selected instruction sequence, said selected instruction sequence followed by a flag-using instruction which uses said flag, said IR tree depending from the one or more of said abstract registers;(c) responding to a first flag-affecting instruction in said selected instruction sequence to cause a flag parameter abstract register to refer to said IR tree generated at step (b); and(d) resolving, in response to detecting said flag-using instruction, a status of said flag with respect to said flag parameter abstract register.