Digital Equipment Corporation

Compaq Information Technologies Group, L.p.

David P Hunter

Richard Lee Sites

William K Colgate

Thomas Van Baak

Paul Geoffrey Lowney

Robert S Cohn

David W Goodwin

Sharon Lea Smith

Computer method and apparatus allows instrumentation of program modules while maintaining exception-handling unwinding context. In the case of instrumenting procedure prologues, the invention preserves the calling context. A sanitized copy of the prologue and rewind instructions to reverse the effects of duplicate prologue instructions are employed.

Computer method and apparatus for safe instrumentation of reverse executable program modules

A compiler-loader system enables the creation of different loaded executable images in target computers complying with different versions of an instruction-set architecture, the different images being created from a single executable program on secondary storage. The compiler generates an executable program containing a routine executable on both versions of the target computers, and also containing an architecture entry with (i) an address of the program location from which the routine is called, (ii) an instruction executable on only one version of the target computers that performs the same function as the routine but with superior performance, and (iii) a value indicating which version of the target machines the instruction can be executed on. The loader determines whether the target machine can execute the instruction, and if so replaces the subroutine call appearing at the address in the architecture entry with the instruction appearing in the architecture entry.

Loader conditionally replacing a code sequence with a functionally-alike

Compiler generating functionally-alike code sequences in an executable

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Mountain View, CA, United States of America

David P Hunter