SPL to HP C/XL Migration Guide (30231-90001)

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Chapter 1 SPL Migration
System Programming Language (SPL) is a language that was developed for
the older HP 3000 computer systems, which currently run under the MPE V
operating system.
HP C/XL is the Hewlett-Packard implementation of the C programming
language on the HP Precision Architecture 900 Series HP 3000 computer
systems, which run under the MPE XL operating system.
This guide will use the terms MPE V and MPE XL to refer to the two
distinct architectures and operating environments.
SPL was designed for systems programmers, in order to give them close
control over the hardware stack, registers, and segmentation of the MPE
V and earlier operating environments. Many SPL features are
hardware-dependent--designed for specific machine instructions and
registers. Most SPL special features are inappropriate for the MPE XL
environment. Many of them are used chiefly to deal with the lack of
space in the MPE V data area, a problem that largely disappears in the
MPE XL environment.
For a general discussion of MPE V to MPE XL migration issues, please read
the
Migration Process Guide and the Switch Programming User's Guide .
Migration Choices
Many programs and systems developed and written in SPL are difficult to
replace. To solve this problem, MPE XL offers a range of migration
options for SPL programs:
* Emulate the MPE V environment with Compatibility Mode.
* Convert the program code with the Object Code Translator.
* Convert source programs to a Native Mode language implemented on MPE
XL machines.
Compatibility Mode
SPL programs may be compiled and run on MPE XL machines immediately,
without code changes. They automatically run in Compatibility Mode,
which emulates the MPE V environment. However, emulation lowers
efficiency, sometimes dramatically.