HP 3000 Manuals HP 3000 Manuals
Native Mode (NM)
Native Mode (NM), or direct execution on a 900 Series computer, allows
use of the following HP Precision Architecture (HPPA) features:
* 32-bit words
* Contiguous memory
* Reduced instruction set
* 64-bit addressing
* Vastly increased stack/code/data space
The 900 Series systems run MPE XL, an extended version of the MPE V/E
operating system.
Full Recompilation
After moving MPE V/E programs over to MPE XL, you will ultimately want to
take advantage of the optimizing NM compilers. Recompilation can involve
source code changes, especially if your application calls routines in
languages not supported in Native Mode or uses MPE V/E features deleted
from, or no longer available on, MPE XL. However, recompilation also
affords the potential for performance gains since recompiled applications
or routines execute directly in the NM environment.
Advantages
Programs running in Native Mode exploit the higher performance and
expanded addressing capabilities of the HP Precision Architecture.
Recompiled applications execute considerably faster than emulated or
translated applications. The optimizing compilers written for MPE
XL-based systems take high-level source code and compile it into NM
object code. NM compiled programs run faster for the following reasons:
* They run directly on the 900 Series machine, rather than being
emulated.
* They make fullest use of the more powerful HPPA instruction set.
* They take advantage of optimizations that the compilers produce by
precisely scheduling and combining the HPPA instructions.
Considerations
For applications where source code is available, recompilation yields
significant improvements in performance, simplicity, ease of maintenance,
and supportability. When source code is not available or the effort of
rewriting is not justified by the potential benefits, you can use the
optimizing Object Code Translator (OCT) to translate MPE V/E-based
programs and SL's. This translator produces significant performance
gains over emulated programs run in Compatibility Mode, at the cost of
code size expansion.