Personally, I don't think people should be relying on 64-bit existing at all.
It is funny that some people even complain about me using more than 16 MiB of combined OS, code and data for "my" (gcc 3.2.3) program and that it is a sign that I have done something wrong and I need to fix "my" code (all 400,000 lines of it). I don't actually agree with that - I think it is reasonable to exceed 16 MiB, which reflects genuine human effort on the part of the programmer who wrote such a massive amount of code (that weighs in at about 3 MB as an executable). But if you need more than 4 GiB it is probably time to rethink your life choices. However, if you intend to go to 64-bit, I think it should be done "properly", ie totally clean - all addresses 64-bit with VD, and you can prove that by putting your executable above 4 GiB (I would prefer 8 GiB for other reasons - staying away from memory subject to theoretical 32-bit negative indexes - on any CPU type) and exposing it to 64-bit addresses. And dutifully copying any code that needs to interface with an AM24 or AM31 service by copying it BTL (preferably once, at program initialization time). That is what I am working towards with my own C library (PDPCLIB). And that cleanliness will assist in porting to other 64-bit environments where there may not be any choice about where your executable gets loaded. BFN. Paul. On Mon, 18 Aug 2025 12:21:46 -0700, Leonard D Woren <[email protected]> wrote: >Just catching up from being away for weeks, there's one thing that >hasn't been mentioned in this long thread about RMODE 64: > >Why is this even needed? > >A load module library filling a 3390-2 will just about fit below the >bar. It greatly simplifies things to run RMODE 31 AMODE 64, with most >of the data above the bar. Then none of this RMODE 64 discussion is >relevant. > >Oh, I suppose if your program is written in one of those bloatware >languages that are used for apps on cellphones, where every rinkydink >trivial app is 30 MB, and big apps can be 500 MB, then you might >possibly need RMODE 64. There is no possible way that anything >written purely in z assembler would ever need RMODE 64. If your data >doesn't fit below the bar, move the data, not the program. > >Part of the product that I work on is in Metal/C, which apparently >generates all code as RMODE 64 AMODE 64. > > >/Leonard > > >---------------------------------------------------------------------- >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
