HP 3000 Manuals HP 3000 Manuals
Removed Limitations The MPE V operating system limits stack space to 65,535 bytes. The virtual memory mechanism of the MPE/iX operating system increases stack space to more than 230 bytes. USLINIT Directive The USLINIT compiler directive is used in HP FORTRAN 77/V to empty the user subprogram library (USL) before placing any object code in it. The USL is a specially formatted file that contains a relocatable binary module for the main procedure, a relocatable binary module for each subprogram, a directory to record information about each of the relocatable binary modules in that library, and information about the program's data stack. The MPE V-based system compilers actively manage user subprogram libraries and write directly to these files. The HP FORTRAN 77/iX compiler creates a new file containing a single object module for each compilation. It never appends to an existing USL file as a compiler on an MPE V-based system does. Furthermore, the need for a USL vanishes since an object module can function as an independent file. Therefore, the USLINIT directive does not exist in HP FORTRAN 77/iX. You can find more information about user subprogram libraries in the Link Editor/iX Reference Manual. MORECOM Directive The MORECOM directive is used in HP FORTRAN 77/V to allow you to allocate more room in a data segment for common variables. The MPE/iX system automatically allocates a much larger area for common variables, so the MORECOM directive is not needed in HP FORTRAN 77/iX. See the Link Editor/iX Reference Manual for more information on data space.