Regprof is a computer program that analyzes the use of registers by another program that runs on a PowerPC

750 (or equivalent) computer. Regprof is useful for showing how well compilers make use of registers and for obtaining an indication of the susceptibility of application programs to radiation-induced changes in register bits. Regprof goes through the source code of the program in question, analyzing each instruction to determine what registers it uses and whether the instruction loads a register with a value or uses a value already in a register. A register is marked as being in use between the instruction that loads a value into it and the last instruction in which that value is used. Upon completion of this analysis, a histogram table that shows how many registers are in use at each line of the analyzed program is printed. One limitation of this analysis is that it does not take account of program flow and, instead, is performed as though all lines of the analyzed code were executed in sequence. This is adequate for most compiler code, but in some cases, one might obtain a distorted representation of register usage.

This program was written by Paul Springer of Caltech for NASA’s Jet Propulsion Laboratory.

This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393- 3425. Refer to NPO-30347.

This Brief includes a Technical Support Package (TSP).
Program Analyzes Use of Registers by Another Program

(reference NPO-30347) is currently available for download from the TSP library.

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This article first appeared in the October, 2002 issue of NASA Tech Briefs Magazine.

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