Since they drop the register addressing with PSW relative addressing they execute faster. Does somebody have a list of S/370 instructions with possible XA/ESA/Z replacements that can directly replaced?
On Thu, May 20, 2021 at 11:47 AM Charles Mills <charl...@mcn.org> wrote: > > If you are a significant coder or maintainer of assembler code, one big > improvement that IIRC no one has mentioned is the relaxation of the base > register nightmare. You know, where you go to make a one-minute change to > some code and you kick it over the 4K boundary and you are faced with three > unappealing choices: commit another register to be an additional base, split > the module in half, or figure out some hack that gets some big data area out > of the basic 4K range. > > The solution is the relatively (ha ha) new branch relative instructions, > commonly referred to as jumps due to their Jxx mnemonics -- plus some other > "relative" instructions such as LARL. A full tutorial is out of scope for a > mailing list e-mail, but the classics comics version is that you replace all > of the Bxx instructions with Jxx, move your data areas to the beginning of > the CSECT with LOCTR, and your 4K base register issues should go away, pretty > much for good. > > Charles > > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On > Behalf Of Steve Estle > Sent: Monday, May 17, 2021 6:42 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Best catch up resources for MVS / ZOS Technologies > > Hello Everyone in Mainframe Land, > > I've been out of the mainframe world since about 2001, but spent the prior 20 > years immersed in that world working with everything from MVS/370 to MVS/ESA > and VM, performance and capacity planning disciplines across a variety of > situations in the IT Services and consulting spaces. I, am, now as a "IT > Infrastructure Engineer- IBM z/OS Mainframe Engineer" after nearly 20 years > of other activities (Project Mgmt, entrepreneur, etc) am about to potentially > come back into a new mainframe role and I need to catch up as quickly as > possible. Any suggestions on ways to fill in the gaps for ZOS, ZVM, > hardware, performance, etc? Bottom line I'm looking for that gap education > to as quickly as possible get up to speed with changes in platforms since > 2001. If prefer to call - all my info is below. > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
