> I once raised a similar question with Peter Relson. He > unequivocally asserted that no program can rely upon any part > of (including the high halves of) the volatile registers > (r15, r0 and r1) being preserved across system interfaces > (unless the interface doc states otherwise). > > Here's the quote: > At 3/18/2007 08:07 AM, Peter Relson wrote: > >Dave, > > > >Except for regs 0,1,15 your assertion is true. > > > >The high halves of those regs are not preserved across any interface > >unless otherwise documented.
I freqently use the full 64-bit R0, R1 and/or R15 registers in 'normal' 31-bit mode programs when I want to do some Grande computing without saving and restoring the upper halves of these registers. This seemed ok after carefully reading the available documentation. Haven't had problems so far.... Fred! ----------------------------------------------------------------- ATTENTION: The information in this electronic mail message is private and confidential, and only intended for the addressee. Should you receive this message by mistake, you are hereby notified that any disclosure, reproduction, distribution or use of this message is strictly prohibited. Please inform the sender by reply transmission and delete the message without copying or opening it. Messages and attachments are scanned for all viruses known. If this message contains password-protected attachments, the files have NOT been scanned for viruses by the ING mail domain. Always scan attachments before opening them. ----------------------------------------------------------------- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
