DOS ain't dead - non-DOS (yet): an interesting project for x86-64

non-DOS (yet): an interesting project for x86-64 (Miscellaneous)

posted by tkchia , 23.01.2021, 15:13

Hello RayeR, Oso2k, and Zyzzle,

> Is it really true that on a system without a true CSM legacy BIOS will be
> completely unable to access real mode or can we create some sort of
> compatibility wrapper in software as an abstraction layer in software to
> enable "bare metal" 16-bit DOS on such systems?

As Japheth mentioned, yes, it is very much possible to switch from 64-bit long mode to real mode.

In fact Intel's own TianoCore UEFI implementation has some code to do just that. The CPU very much supports going from long mode to real mode. The problem in getting an "abstraction layer" working is mainly in the stuff outside of the CPU (again, ACPI... :-| ).

Thank you!

---
https://gitlab.com/tkchia · https://codeberg.org/tkchia · 😴 "MOV AX,0D500H+CMOS_REG_D+NMI"

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Complete thread:

non-DOS (yet): an interesting project for x86-64 - effebi68, 18.01.2021, 08:57 (Miscellaneous)
- non-DOS (yet): an interesting project for x86-64 - glennmcc, 19.01.2021, 17:52
  - non-DOS (yet): an interesting project for x86-64 - effebi68, 19.01.2021, 18:35
  - non-DOS (yet): an interesting project for x86-64 - ecm, 19.01.2021, 18:57
    - non-DOS (yet): an interesting project for x86-64 - RayeR, 19.01.2021, 19:14
      - non-DOS (yet): an interesting project for x86-64 - ecm, 19.01.2021, 20:01
    - non-DOS (yet): an interesting project for x86-64 - glennmcc, 20.01.2021, 07:16
      - non-DOS (yet): an interesting project for x86-64 - tkchia, 21.01.2021, 17:42
        non-DOS (yet): an interesting project for x86-64 - ecm, 21.01.2021, 18:24
        non-DOS (yet): an interesting project for x86-64 - tkchia, 21.01.2021, 18:40
        non-DOS (yet): an interesting project for x86-64 - RayeR, 21.01.2021, 18:57
        non-DOS (yet): an interesting project for x86-64 - Oso2k, 23.01.2021, 05:26
        non-DOS (yet): an interesting project for x86-64 - Zyzzle, 23.01.2021, 07:03
        non-DOS (yet): an interesting project for x86-64 - tkchia, 23.01.2021, 15:13
        non-DOS (yet): an interesting project for x86-64 - RayeR, 23.01.2021, 20:35
        non-DOS (yet): an interesting project for x86-64 - tkchia, 24.01.2021, 04:20
        non-DOS (yet): an interesting project for x86-64 - RayeR, 25.01.2021, 17:34
        non-DOS (yet): an interesting project for x86-64 - Japheth, 23.01.2021, 08:52
        non-DOS (yet): an interesting project for x86-64 - glennmcc, 23.01.2021, 17:38
        non-DOS (yet): an interesting project for x86-64 - tkchia, 23.01.2021, 18:31
        non-DOS (yet): an interesting project for x86-64 - glennmcc, 23.01.2021, 21:07
        non-DOS (yet): an interesting project for x86-64 - tom, 23.01.2021, 23:31
        non-DOS (yet): an interesting project for x86-64 - glennmcc, 24.01.2021, 02:56
        non-DOS (yet): an interesting project for x86-64 - tkchia, 24.01.2021, 04:34
        non-DOS (yet): an interesting project for x86-64 - glennmcc, 24.01.2021, 05:17
        non-DOS (yet): an interesting project for x86-64 - tkchia, 24.01.2021, 06:26
        non-DOS (yet): an interesting project for x86-64 - glennmcc, 25.01.2021, 03:30
        non-DOS (yet): an interesting project for x86-64 - rr, 25.01.2021, 13:05
        non-DOS (yet): an interesting project for x86-64 - glennmcc, 27.01.2021, 04:03
        non-DOS (yet): an interesting project for x86-64 - tkchia, 27.01.2021, 07:04
        non-DOS (yet): an interesting project for x86-64 - RayeR, 25.01.2021, 17:51
        non-DOS (yet): an interesting project for x86-64 - tkchia, 24.01.2021, 03:59
        non-DOS (yet): an interesting project for x86-64 - tkchia, 20.07.2021, 10:29
- non-DOS (yet): an interesting project for x86-64 - tkchia, 15.11.2022, 08:44