> I am on a z/os 2.2 system, trying to rseurrect some old code. > . > can some one confirm the instructions for Searching the > Address Space Vector Table (ASVT) on z/OS 2.2 > . > This program loads R10 with CVTASVT > L R10,CVTASVT GET ASVT ADDRESS > USING ASVT,R10 ESTABLISH ADDRESSABILITY > . > It then issues a Load Address For the first entry ? > This doesn't look correct to me ? > LA R11,ASVTENTY GET # OF FIRST ENTRY > . > Next its test for an ASCB that is assigned. > TM 0(R11),ASVTAVAL VALID ASCB Available ? > BO RUNLOP1 NO, CHECK NEXT ASVT ENTRY > . > * Examine ASCB > . > The current code issues the following instruction, which > looks incorrect according to IHAASVT > LA R11,4(,R11) Advance NEXT ASVT ENTRY
ASVT mapping: https://www.ibm.com/docs/en/zos/2.2.0?topic=information-asvt-mapping That looks correct to me. Here's some code from MVS3.8 IEAVEAC0: L R1,CVTASVT-CVT(R1) GET THE ASVT 63660002 BCTR R13,ZERO ASID-1 63710002 SLL R13,TWO (ASID-1) X 4 63730002 L R13,ASVTENTY-ASVT(R13,R1) GET ASCB ADDRESS @YM01596 63750002 So each slot in the ASVT is a 4 byte pointer with the high bit off if points to an ASCB. ASID 0 doesn't exist, so ASVTENTY is the pointer for ASID 1. It does need some check to not run off the end of the ASVT... https://www.ibm.com/docs/en/zos/2.2.0?topic=information-asvt-heading Size: Offset of ASVTEND minus offset of ASVTBEGN plus four times the value of ASVTMAXU. I'd guess that there are ASVTMAXU 4 byte entries starting and counting ASVTENTY. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
