CP/M-386 Project Initiates Development for 386 Protected Mode

Project Overview

CP/M-386 is a new project focused on implementing CP/M for 386 protected mode environments. The project is currently in its initial development stages, building upon the foundation of CP/M-68K.

This implementation features a full 32-bit protected mode with Ring-3 TPA and can be booted via a 3.5-inch 1.44MB floppy disk MBR or GRUB Multiboot kernel. It supports VGA text and COM1 serial consoles.

Hardware and System Compatibility

CP/M-386 is designed to be compatible with 386 and later systems that have 2MB or more of memory. It supports systems utilizing either PC BIOS or UEFI with CSM.

Currently supported hardware includes VGA, 8042 PS/2, 8250/16450/16550 UART, CMOS RTC, and 8253/8254 PIT. Drivers for floppy, hard disk, CD, USB, network, and sound are not yet implemented.

CP/M Compatibility and Extensions

The system reports BDOS 2.2 to applications and aims for high source compatibility with other CP/M implementations. The CP/M-386 BDOS achieves full parity with CP/M-68K 1.3 and CP/M 2.2.

A significant portion of CP/M-Plus (CP/M 3) BDOS is supported, along with over 60% of DOS-Plus additions and approximately half of MP/M extensions. Missing functionality primarily relates to multi-user and multi-tasking features not applicable to a single-user CP/M. Unique CP/M-386-specific BDOS extensions have been added for features like direct video access and high-resolution timing.

Build Requirements and Supported Environments

To compile CP/M-386, dependencies include AWK, Cpmtools (version 2.23 or later), GNU Binutils, GNU Coreutils, GNU GCC or LLVM Clang, GNU Make, NASM, and QEMU for testing.

Building is supported on current releases of NetBSD, FreeBSD, and recent Linux distributions. Verified Linux distributions include CentOS Stream 9, Fedora 36, Debian 12, Ubuntu 18.04 (with gcc-16), Ubuntu 22.04, Alpine 3.24, and OpenSUSE Leap 15.4.