Inventors:
David P. Hunter - Mountain View CA
William K. Colgate - Issaquah WA
Richard L. Sites - Menlo Park CA
Thomas Van Baak - Bellevue WA
Assignee:
Digital Equipment Corporation - Maynard MA
International Classification:
G06F 945
Abstract:
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.