Steven P Hobbs

US Patent:

6675374, Jan 6, 2004

Filed:

Oct 12, 1999

Appl. No.:

09/416436

Inventors:

John Samuel Pieper - Mont Vernon NH
Steven Orodon Hobbs - Westford MA
Stephen Corridon Root - Westboro MA

Assignee:

Hewlett-Packard Development Company, L.P. - Houston TX

International Classification:

G06F 945

US Classification:

717141, 717131, 717142, 717154, 712235, 712237

Abstract:

A technique is provided for inserting memory prefetch instructions only at appropriate locations in program code. The instructions are inserted into the program code such that, when the code is executed, the speed and efficiency of execution of the code may be improved, cache conflicts arising from execution of the prefetch instruction may be substantially eliminated, and the number of simultaneously-executing memory prefetch operations may be limited to prevent stalling and/or overtaxing of the processor executing the code.

US Patent:

56131178, Mar 18, 1997

Filed:

Apr 20, 1994

Appl. No.:

8/231441

Inventors:

Caroline S. Davidson - Hollis NH
Richard B. Grove - Westford MA
Steven O. Hobbs - Westford MA

Assignee:

Digital Equipment Corporation - Maynard MA

International Classification:

G06F 300
G06F 500

US Classification:

395708

Abstract:

A compiler framework uses a generic "shell" and a generic back end (where the code generator is target-specific). The generic back end provides the functions of optimization, register and memory allocation, and code generation. The code generation function of the back end may be targeted for any of a number of computer architectures. A front end is tailored for each different source language, such as Cobol, Fortran, Pascal, C, C++, etc. The front end scans and parses the source code modules, and generates from them an intermediate language representation of the source code programs expressed in the source code. The intermediate language represents any of the source code languages in a universal manner, so the interface between the front end and back end is of a standard format, and need not be rewritten for each language-specific front end. A feature is a method for doing code generation using code templates in a multipass manner. The selection and application of code templates occurs at four different times during the compilation process: (1) A pattern select phase does a pattern match in a context pass to select the best code templates; (2) Tasks of the context pass use context actions of the selected templates to analyze the evaluation order to expressions and to allocate temporary names; (3) A bind pass uses the binding actions of the selected templates to allocate template names; (4) Finally, a code pass uses code generation actions of the selected templates to guide the generation of object code.

US Patent:

54936756, Feb 20, 1996

Filed:

May 26, 1994

Appl. No.:

8/249670

Inventors:

Robert N. Faiman - Wilton NH
David S. Blickstein - Hudsoon NH
Steven O. Hobbs - Westford MA

Assignee:

Digital Equipment Corporation - Maynard MA

International Classification:

G06F 300
G06F 500

US Classification:

395700

Abstract:

A compiler framework uses a generic "shell" and a generic back end (where the code generator is target-specific). The generic back end provides the functions of optimization, register and memory allocation, and code generation. The code generation function of the back end may be targeted for any of a number of computer architectures. A front end is tailored for each different source language, such as Cobol, Fortran, Pascal, C, C++, etc. The front end scans and parses the source code modules, and generates from them an intermediate language representation of the source code programs expressed in the source code. The intermediate language represents any of the source code languages in a universal manner, so the interface between the front end and back end is of a standard format, and need not be rewritten for each language-specific front end. A feature is a mechanism for representing effects and dependencies in the interface between front end and back end. An element has an effect if it writes to memory, and has a dependency if it reads from a location which some other node may write to.