Peter, thanks for responding. I'm familiar with coding SVCs, the different types and RBs.
This is an existing AMODE31 user SVC routine that needs to be updated to start tolerating AMODE64 addresses. So my question still is whether everything I need to know about coding such AMODE64 to AMODE31 stepdown logic has already been covered in the forum thread from August, which I previously linked to: http://bama.ua.edu/cgi-bin/wa?A2=ind0708&L=ibm- main&D=0&amp;I=1&X=&P=181834 Jerry On Tue, 15 Jan 2008 12:27:41 -0500, Peter Relson <[EMAIL PROTECTED]> wrote: >The SVC FLIH will happily give control to the SVC routine in whatever mode >the SVC routine is defined to get control, regardless of what AMODE the >SVC-issuing program was in. > >It is up to the SVC routine to decide what to do about that, often basing >its decisions on that caller's AMODE, as located from the RB (which RB >depends on the type of the SVC). > >Most existing SVC routines chose to change nothing, thus ending up treating >the AMODE 64 issuer exactly the same as an AMODE 31 issuer (this is one key >reason that AMODE 64 is indicated both by PSW bit 31 and PSW bit 32). By >choosing to change nothing, the SVC routine, in effect, chose to restrict >the AMODE 64 caller from providing data above 2G. It could, of course, have >changed to allow that. > >Peter Relson >z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
