Unisys Corporation

Jason D Sollom

James A Williams

Christopher M Cischke

Techniques are described for emulating an instruction processor for use during the development of a computer system. Specifically, the techniques describe an emulated instruction processor that accurately and efficiently emulates an instruction processor having separate interfaces to fetch op-codes and operands. Further, the emulated instruction processor may provide detection of errors associated with the separate interfaces. By making use of the techniques described herein, detailed information relating to errors associated with the memory architecture may be gathered for use in verifying components within the memory architecture, such as first and second-level caches.

Instruction processor emulator having separate operand and op-code interfaces

Techniques are described for emulating inter-processor communications between multiple instruction processors. The techniques provide inter-processor message accounting and error detection. A system, for example, includes software executing within an emulation environment provided by a computing system. The emulation software emulates an instruction processor having an interface to receive inter-processor messages. During emulation the emulated instruction processor calculates an actual count of the inter-processor messages received during emulation. A compiler executing on the computing system compiles test software to output an instruction stream for execution by the emulated instruction processor. The compiler calculates an expected count of inter-processor messages that the emulated instruction processor is expected to receive during emulation. Emulation control software executing on the computing system generates a report that presents the expected count of the inter-processor messages and the actual count of the inter-processor messages.

Instruction processor emulation having inter-processor messaging accounting

Techniques are described for accurately and efficiently emulating an instruction processor having a write buffer. The described techniques may be utilized to quickly develop an emulated instruction processor that provides a fully-functional write buffer interface in an efficient and elegant manner. For example, a system is described that includes a computing system that provides an emulation environment, and software executing within the emulation environment that emulates an instruction processor having a write buffer interface and a memory interface. The software emulates the instruction processor by selectively outputting a write request on the write buffer interface or the memory interface in response to an emulation control instruction embedded within an instruction stream.

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Champlin, MN, United States of America

Jason D Sollom