DOS ain't dead

CM16 (Developers)

posted by kerravon , Sydney, Free World South, 28.04.2025, 15:40

I was thinking about RM16.

Is it possible to bank out everything - the BIOS ROM etc - to get access to the underlying memory?

Because I can run with interrupts disabled, and the OS in low memory, so that when I'm ready for screen output I bank the video back in, and the BIOS back in, and call it.

If I set AHINCR to 0FFF and only run huge memory model programs (and export the OS C library too so that not every app needs to provide that), I could have memory tiled similar to how CM16 is working, but with segments like this:

0000
0FFF
1FFE
2FFD
3FFC
4FFB
5FFA
6FF9
7FF8
8FF7
9FF6
AFF5
BFF4
CFF3
DFF2
EFF1
FFF0

and that way I could access almost all of the memory, including the upper 64k, without having to write non-portable code for the memory management.

Otherwise I would need exception code and exception apps for that top 64k.

Although that won't help with AHSHIFT code. But I can use Watcom instead so that I am not constrained by these things.

Complete thread:

• CM16 - kerravon, 06.04.2025, 21:30 (Developers)
  • CM16 - Japheth, 07.04.2025, 15:48
    • CM16 - kerravon, 09.04.2025, 10:05
      • CM16 - kerravon, 27.04.2025, 17:24
        • CM16 - kerravon, 27.04.2025, 18:36
          • CM16 - kerravon, 27.04.2025, 19:57
            • CM16 - kerravon, 27.04.2025, 20:15
              • CM16 - kerravon, 28.04.2025, 15:40