[Sunrisepeak]

openkal-dos 0.1.0 is an implementation of openkal on DOS, through a DPMI host. It is a technical experiment only and carries no stability guarantee.

Contents

• Stub (stub/stub.S, 2544 bytes). An MZ program in 16-bit code. It finds a 32-bit DPMI host and otherwise runs CWSDPMI.EXE from the program's directory. It enters protected mode as a 32-bit client, loads the ELF32 i386 executable (ET_EXEC, base 0x1000) into one block and hands over a record (src/dos.h, version 1).
• Interfaces.
  • openkal.fs (files).
  • openkal.terminal (the console).
  • openkal.exec (executable memory).
  • The environment, time, memory, stream and abort.
  • openkal.region is absent, as measured.
• Faults. A processor fault (#DE, #UD, #SS, #GP, #PF) is reported on standard error, through DPMI 0203h handlers. The program ends with 128 plus the signal's number: 136, 132 or 139. Without the handlers, CWSDPMI prints a register dump on the screen and ends with status 1.
• okdos (package openkal-dos-tools). okdos seal writes the stub before an executable; okdos check reports whether a file is such a program.
• Conventions. The target is a 486: -march=i486. DOSBox Staging 0.83 executes no CMPXCHG8B under any cputype.

CI

• stub: build.sh reproduces the committed stub byte for byte.
• okdos: built and refusing a plain file on Linux, macOS and Windows.
• programs: examples/hello in dev and release returns 7, tests/files returns 9 and tests/fault returns 139, under DOSBox Staging through dirun.

The programs job builds through openkal-platform 0.28.0 (row i686-dos-musl). It passes once that release and mcpp 2026.11.13.1 are published.

Verified locally

Using the platform at a local path, the programs return 7 (dev), 7 (release), 9 (files) and 139 (fault). The stub is reproducible.

CWSDPMI is distributed under its own terms; it is fetched by the runner's package and not carried here.