On Mon, 29 Nov 2010 11:22:43 -0600 "McKown, John" <john.mck...@healthmarkets.com> wrote:
:>> -----Original Message----- :>> From: IBM Mainframe Discussion List :>> [mailto:ibm-m...@bama.ua.edu] On Behalf Of Tom Marchant :>> Sent: Monday, November 29, 2010 11:11 AM :>> To: IBM-MAIN@bama.ua.edu :>> Subject: Re: IEFBR14 :>> On Mon, 29 Nov 2010 10:51:19 -0600, Chase, John wrote: :>> >Wasn't there also a requirement that whatever means was :>> chosen to zero :>> >Reg15 also set the condition code to zero? :>> The condition code for the step is set from the value in register 15. :>> There is no connection between that and the condition code bits in :>> the PSW. No, there was no requirement to set the CC bits in the PSW. :>Now that would be interesting, tho. Most code does something like: :> CALL SOMEPGM,... :> LTR 15,15 :> BNZ ERROR :>Imagine if IBM had stated that that subroutine linkage should set the CC as well as the RC in 15 so that the code could have been shorted to: :> CALL SOMEPGM,... :> BNZ ERROR :>I saved 2 bytes and one instruction. Today, who cares? On an old S/360??? IIRC, that is how it works in CP (VM). But it required the called routine to set the CC, typically via SPM. -- Binyamin Dissen <bdis...@dissensoftware.com> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- 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
