Who is disadvantaged by making memory above 2 GiB available to anyone who specifically requests it?
BFN. Paul. On Sun, 6 May 2018 15:23:38 -0400, Tony Thigpen <[email protected]> wrote: >Bad idea. The 31bit bar is there for a very, very good reason. > >Tony Thigpen > >Paul Edwards wrote on 05/06/2018 02:51 PM: >> Hi. I would like to submit an RFE to IBM to >> support a LOC=32 parameter to GETMAIN, >> giving 32-bit programs access to a full 4 GiB >> instead of the current 2 GiB provided by >> LOC=31. IBM can use the LOC=31 bits >> plus the top bit of the option byte seen here: >> >> https://www.ibm.com/support/knowledgecenter/SSLTBW_2.3.0/com.ibm.zos.v2r3.ieav200/svc120.htm >> >> When the GETMAIN is executed in AM64, >> memory above 2 GiB is potentially returned. >> When executed in AM31, normal LOC=31 >> memory is obtained instead. This way the >> application will still work on older systems >> that aren't LOC=32 aware. >> >> When obtaining LOC=32 memory, the GETMAIN >> routine should search *down* the free memory >> chain to find a free area, to preserve the LOC=31 >> space. >> >> It is up to the application program to ensure that >> when manipulating the LOC=32 memory it is in >> AM64 and while in AM64 it does not attempt to >> use the top bit of any 32-bit register as a flag. >> >> After I submit the RFE it would be good if people >> could upvote it. What is the best wording I can >> use so that IBM understands what I am asking >> for and doesn't reject it? >> >> Thanks. Paul. >> >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO IBM-MAIN >> >> > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
