FWIW, I use R0-R15 for32-bit registers and RW0-RW15 for 64-bit. On Jul 31, 2013 5:37 PM, "Paul Gilmartin" <[email protected]> wrote:
> On 2013-07-31 15:01, Gerhard Postpischil wrote: > > On 7/31/2013 1:44 PM, Bernd Oppolzer wrote: > >> When I came to the site where I am actually working 25 years ago, > >> I was very surprised that they use RA to RF for 10 to 15 - I never met > >> that before, but you get accustomed to that very quickly. It's always > >> two characters, after all ... > > > > I first came across this form in the OS/360 reader/interpreter. > > Personally I don't like it because searches on RB and RE get many more > > false hits than R11 and R14. > > > And, of course, since there's no standard, the system macros > must use pure numeric designators. And with a mixture of > conventions, XREF doesn't reliably list register references. > IATYREGS is somewhat unusual among IBM macros in that it sets > a flag so it can exit if it's used twice, and some other JES3 > macros invoke IATYREGS so they _can_ use register mnemonics. > > I think I've also seen GR0-GR15, which likewise reduces the > likelihood of false hits in searches. > > CDC 6600 et al. made the register names predefined, reserved, > and mandatory. It was impossible to confuse L and LR; the > operands distinguish them. And no need for unintuitive > conventions such as "7" means constant 7 and "(7)" means > register 7 in macro arguments. It was "7" or "X7". So, no > need for such as IHBINRRA. And less incentive to print macro > expansions; they did what they appeared to from the call. > > -- gil >
