Sharuff, >> I'm interested about what assembler code 'out there' (zOS,zVM or zVSE) still contained (probably as dual code path?) XA or 370 or 390 only code path/instructions - and why.
24 - 31 - XA (btw: what part is XA) is the sequence of things that became available of the MF and IBM did an excellent job to be compatible. So something written after the advent of 31 and not compatible with 24 (without dual-pathing) is something that should not be. Programs might not be able to utilize 24 bit mode all the time because they deal with things that are only available below the line, but new programs can be written such that they can run above (if available) and utilize facilities that are only available below the line. The famous example is BSAM. Now dealing with 64 bit mode (or using some of the new instructions like i.e. POPCNT) in programs written for more than one installation (vendor code) is a different animal IMHO. Just answering the original 64 bit question (from my VSE tower): System will always be able to answer a request for 64 bit - If you make it conditional it will tell you that it resolved from below the bar (if the area above the bar is exhausted). Scott, what would stop you using z-arch-instructions to handle it? -- Martin Pi_cap_CPU - all you ever need around MWLC/SCRT/CMT in z/VSE more at http://www.picapcpu.de
