johnsonjh/cpm386: CP/M-386: CP/M for 386 protected mode, derived from CP/M-68K · GitHub

CP/M‑386 is CP/M for 386 protected mode, derived from CP/M‑68K.

CP/M‑386 is currently in the very early development stages.

• Compatible with 386 (and later systems) with 2MB (or more) memory.
• Systems using either PC BIOS or UEFI (with CSM) are supported.
• VGA, 8042 PS/2, 8250/16450/16550 UART, CMOS RTC, and 8253/8254 PIT
  are supported.

CP/M‑386 should be highly source‑compatible with other implementations:

The system currently reports BDOS 2.2 to applications.

• The CP/M‑386 BDOS is at full parity with CP/M‑68K 1.3 and
  CP/M 2.2.
• A large majority of the CP/M‑Plus (CP/M 3) BDOS is also
  supported.
• More than 60% of the DOS‑Plus additions have been implemented.
• Approximately half of the MP/M extensions have been completed.
  • The missing functionality is largely the multi‑user, multi‑tasking,
    message queuing, and process control calls that don’t apply to a
    single‑user CP/M implementation.
• Unique CP/M‑386‑specific BDOS extensions have been added to accommodate
  new features like direct video access, high‑resolution timing, PRNG, etc.

The following dependencies are required to compile CP/M‑386:

^†Be sure to use cpmtools version 2.23 or later. Older
versions may appear to work but have several known bugs.

Building CP/M‑386 is supported on current releases of NetBSD and
FreeBSD^‡, and most recent Linux distributions.

The following are the minimum versions of Linux distributions that have been
verified to build CP/M‑386 successfully: CentOS Stream 9, Fedora 36,
Debian 12, Ubuntu 18.04 (with gcc-16 from ppa:ubuntu-toolchain-r/test),
Ubuntu 22.04, Alpine 3.24, and OpenSUSE Leap 15.4.

• GCC build (recommended):

  make -Orecurse -j "$(nproc 2> /dev/null || printf '%s' 1)"
  make test

• Clang build:

  make -Orecurse -j "$(nproc 2> /dev/null || printf '%s' 1)" CC="clang"

• It is recommended to use GCC as Clang‑compiled i386 code is larger.
• Be sure to make clean if switching compilers or adjusting compiler flags.
• 32‑bit support libraries are required to run the test suite (make test).
• ^‡At the time of writing, FreeBSD is shipping non‑functional
  cpmtools2 packages with broken mkfs.cpm functionality. To successfully
  build on FreeBSD, you must rebuild cpmtools and ensure it is not
  linked with libdsk. If you receive a Disc rejected by driver error on
  FreeBSD from mkfs.cpm, your tools are broken and cannot be used to
  build CP/M‑386.

You can download pre‑compiled binaries above.

• Multiboot
  kernel (recommended):

  qemu-system-i386 -m 2M -serial stdio -monitor none -kernel "cpm386.elf"

• Floppy MBR loader:

  qemu-system-i386 -m 2M -serial stdio -monitor none -drive if=floppy,format=raw,file="floppy.img" -boot a

• Use -nographic -display none -vga none to disable VGA video (and use only serial console).
• Use -serial none to disable the serial UART (and use only VGA console).

• Do not open pull requests with large amounts of LLM‑generated code.
  These will be immediately rejected.
• There is currently no AI‑generated code in the operating system at this
  time (though there are some AI tests, comments, and analysis), as the
  project is intended to be as much of a learning experience for me as it is
  a useful OS port.
• Usage of AI (artificial intelligence) tools by contributors is currently
  permitted, subject to the same terms and conditions as the
  LLVM AI Tool Use Policy, but
  this permission may be withdrawn at any time and without notice.

See FUTURE.md.

• CP/M‑386 is distributed under the terms of the permissive
  MIT License.
• Bryan W. Sparks of DRDOS, Inc. dba DeviceLogics LLC, successor
  in interest to Digital Research, Inc.’s CP/M assets, explicitly
  grants an unlimited authorization to use, distribute, modify, enhance, and
  otherwise make available CP/M technology, including the CP/M operating
  systems and their derivatives.