Sun Microsystems, Inc.

Sunil Sreenivasan

David Dice

David K Aha

An operating system call control subsystem is disclosed for use in a computer that includes a processor for processing a program, the program instructions of an operating system call instruction type identifying one of a plurality of types of operating system calls, each type of operating system call being associable with an operating system call type identifier value within a predetermined range of values. The operating system call control subsystem comprises a crossover table, an operating system call instruction type address resolution module, and an operating system call instruction type processing module. The crossover table has a number of entries corresponding to a predetermined fraction of the predetermined range, each entry in the crossover table having an instruction for enabling the processor to save a value corresponding to an offset of the entry into the crossover table. The operating system call instruction type address resolution module provides the instructions of the operating system call instruction type with respective target addresses that include an operating system call set identifier in a set of operating system call set identifiers, the number of operating system call set identifiers multiplied by the number of crossover table entries corresponding to the predetermined range and an offset value corresponding to an offset to an entry into the crossover table. The operating system call instruction type processing module, in response to the processor processing an instruction of the operating system call instruction type, (a) saves the operating system call set identifier from the target address, (b) selects one of the entries in the crossover table using the offset value of the target address, (c) processes the instruction from the selected entry of the crossover table to save the value corresponding to the offset of the selected entry in the crossover table, and (d) generates the operating system call type identifier value in connection with the saved operating system call set identifier and the saved value corresponding to the offset of the selected entry in the crossover table.

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Mt. Kisco, NY, United States of America

Sunil Sreenivasan