H89 Emulator - The Virtual H89 All-in-One Computer

This project is currently under develop. A release will be coming shortly.

Video clip of the Emulator

A quick little clip of the emulator running the snake game:

Goals

To work with both CP/M and HDOS (and UCSD Pascal, if I can find an image of it).
Clock accurate emulation of the entire system. (Be able to play fast-action graphic games). Option to run emulator at 'max speed'.
Emulation of the H19 Terminal functions (including accurate character and graphic representation). Accurate baud rate between the computer and terminal.
Be able to select hardware options of the system, i.e. amount of memory, which ROM, which controllers, add-on disk drive systems.
Portable to a wide-range of the platforms (Windows, Linux, Mac, etc.).
Written in C++.

Status - The current code is being cleaned-up. I'd like to have the details of the disk formats handled before releasing the initial version of the emulator. I hope to have a beta release of the Emulator in the next few weeks. Current requirements will be a Mac running Leopard (OS X 10.5) and graphics that are better than Intel integrated graphics.

Virtual H89 OS Status Table

OS	Status	Comments
HDOS 1.0 (Issue #50.00.00 890-1)	Does not Boot	This initial release of HDOS appears to be hard-coded for the H8's 8251 UART. Since the H89 does not use an 8251 for the console port or even the same address as the H8, the H89 emulator will not support this initial release of Version 1.0.
HDOS 1.0 (Issue #50.03.00 890-1-3)	Boots	This release of version 1.0 supports the 8250 serial port and currently boots on the emulator. No obvious problems, except for INIT.
HDOS 1.5 (Issue #50.04.00 890-1-4)	Boots	No obvious problems, except for INIT.
HDOS 1.6 (Issue #50.05.00 890-1-5)	Boots	No obvious problems, except for INIT.
HDOS 2.0 (Issue #50.06.00 890-64)	Boots	No obvious problems. Writing works. INIT is not working.
HDOS 3.02 (Issue #50.07.00)	Boots	A hard-sectored HDOS 3.02 boot disk was located by Les Bird. This disk image boots without any obvious problems, except for INIT.
CP/M 2.2.02	Boots	No obvious problems. Writing appears to work. DUP works. FORMAT does not work. SYSGEN appears to work
CP/M 2.2.03	Boots	The configur.com program now correctly autodetects the virtual floppy drives, there was 2 flags in the H17 status register that needed to be set. FORMAT does not work.
CP/M 2.2.04	Boots	Configur.com and the extra 'Setup' Disk correctly detects the virtual disk drives. DUP works. FORMAT does not work. SYSGEN appears to work.
UCSD Pascal	Unknown	I do not have UCSD Pascal (actual disk or images) to test. I would love to get a copy - please contact me at the email address below, if you have UCSD Pascal for the H/Z-89.

- The OpenGL / H19 terminal emulation (in progress) is integrated in to the CPU emulator and displays graphic characters/reverse video and processes many of the ESC sequences. Add support for a blinking cursor, either underlined or block.

H89 Screen dump

More screenshots below.

Z80 Emulation selection (done)

Examined both z80pack and yaze-ag. Both are good, but z80pack provides the option to run at a given speed.
Started with z80pack.

Encapsulated the Z80 emulation into a new C++ class (done - but may need further refinement).
Added support for interrupt mode 0 (done - only supports RST xx instructions).
Updated the code to have accurate flag handling on some of the rarely used instructions. (done - documented behavior appears complete and accurate)
Abstracted the memory / address bus (done)
Adding support for more 'undocumented' opcodes as defined in "The Undocumented Z80 Documented". (In progress - low priority)

Phase 1 (Done)

Support for both ROM and RAM objects are implemented(done)

The Monitor ROM (MTR-90-1) is running.

2 ms timer works on Mac OS X (done).

Changed the way the accurate clock emulation was coded, it now uses an interval timer instead of sleep() calls. (The existing code did not appear to take into account the amount of time executing instructions. Although on a current computer, this time was < 3% with the generic CP/M system z80pack provides. This could be a problem on slower systems or as more code is added for the emulator.)
Interrupts are working.
A 2 mSec timer works for Leopard (10.5.x), but not on Tiger (10.4.x). A redesign will be needed to work on systems that only support a 10 mSec timer, this currently is low priority, since it appears that Linux also supports a 2 mSec timer. (todo).

Basic 8250 Serial port support (Done).

Very rudimentary support for the 8250 is complete. Input and output of characters work. But further work is needed to fully implement the 8250 into a C++ class.
Need to add more support for baud rate selection/detection, mismatches between terminal/computer and the 'spaces' baud selection in HDOS not working properly(todo)

Phases 2/3 (In progress)

Implementing the H-88-1 (Hard-sectored controller). Found the H17 ROM listing, which helps.

The Disk rotational speed test (Go 7372) is working(done)
Boot (done)

HDOS (done).

V.1.0 - one of two 1.0 versions is working.

890-1 Version only supported 8251 serial port which an H89 does not have, I expect that this version will only work on an H8 with an H-8-5 Serial/Cassette Interface board.
890-1-3 Version supporting 8250 serial port working

V.1.5 working
V.1.6 working
V.2.0 working

CP/M (done)

2.2.02 working
2.2.03 working
2.2.04 working

Writing(in progress)

Writing to images that have already been FORMATed (CP/M) or INITed (HDOS) is working

the changes to the disk last until while the program is running, and are written out to a new file.

FORMAT(cp/m) and INIT(hdos) is not working.

Saving Disk Images(in progess)

Currently saving disk image to a new file - working.

The Z-89-37 - soft-sectored controller (investigating - may be delayed to a later phase)
The Z-89-47 - 8" controller (likely to be delayed to a later phase)
The Z-89-67 - Winchester controller (likely to be delayed to a later phase)
Working on H19 emulation from phase 3.

accurate font (imported from ROM - done)
accurate speed - 9600 baud (partially done - behaves like speed is 9600, but HDOS thinks it's 2400)
rendered in OpenGL, basic rendering, graphic symbols, reverse video (done)
Design H19 class to emulate terminal (done)
Complete emulation of Serial Port 8250 chip(partially done).
Complete H19 processing of all Heathkit ESC sequences (in progress)
Handling of ANSI ESC Sequences (delayed to a later phase)

Phase 4+ (Not yet started)

Plan

Start with an existing Z80 Emulator (z80pack appears to be a good option - it includes interrupts and the ability to run the Z80 at a specific speed).
Phase 1 - get it to the "H:" prompt, i.e. have it work with the Monitor ROM.

Configure the memory to support some mappable ROM images below 8k.
Add a 2 ms timer (hopefully host OSes will allow this resolution).
Add support for very basic I/O including the 8250 serial chip that communicates to the built-in terminal.

Phase 2 - add support for disk systems.

Add support for H17 (H-88-1 controller - top priority).
Add support for H37 (Z-89-37 controller) (likely to be pushed out to a later phase).
Add support for H47 (8" Floppy Disks - Z-89-47 controller - likely to be pushed out to a later phase).
Add support for H67 (8" Winchester 10M drive - Z-89-67 controller - likely to be pushed out to a later phase).

Phase 3 - work on H19 emulation.

Accurate speed (9600 baud).
Accurate graphic characters.
Accurate text characters
Accurate handling of all the escape sequences (Heath).
Complete emulation of Serial Port 8250 chip.
Accurate handling of the ANSI mode (likely to be pushed out to a later phase).

Phase 4 - options to select system configuration.

Selectable disk controller(s)
Selectable drives - H-17-1 (SS 48tpi) or H-17-4/5(DS 96tpi) or Generic DS 48 tpi.
Selectable amount of RAM - 16k, 32k, 48k, or 64k.
Selectable Monitor ROM

MTR-88
MTR-89
MTR-90
MTR-90-1

Selectable screen color

White
Amber
Green
User selectable.

Phase 5 -Add-on cards

Full support for HA-88-3 Serial card.

Connect a port to a physical USB->Serial on host.
Connect to other virtual devices (other virtual H89s, Votrax Talk-n-type, printer, modem, etc).

Support for Z-89-11 Parallel card
Add real floppy drive sounds for seek and read/write operations.
Support H-88-5 Cassette Interface card/Virtual tape drive

(real tape sound - be able to read/write audio files).

Third-party add-in cards

Graphics

Cleveland Codonics
New Orleans General Data Services (NOGDS)
SigmaSoft

Sound
Memory >64k (memory banks)

Magnolia Microsystems 128K RAM
DG Super 89

Peripherals

Printers - write to PDF file or directly to a printer

H14 Printer, accurate symbols
H25

Modems

Be able to connect to the host computer to transfer files.
Selectable baud rates.

Votrax Talk-n-Type

Phase 6 - graphic front-end

Option to make it look like you are sitting in front of a real H89 system.
Option for accurate screen - flicker, curved tube, tube persistence..

Phase x - anything that has been pushed out.
Phase y - Emulate an H8 computer

H9 Terminal
H10 Paper Tape
Cassette Tape storage
H19 Terminal (should be very little change from the H89 code)
H29 Terminal
H17 Floppy (should be very little change from the H89 code)

Additional Screen dumps of CP/M booting on the virtual H89. All CP/M versions are now correctly autodetecting the 3 (virtual) disk drives.

H89 Screen dump - CP/M 2.2.02

H89 Screen dump - CP/M 2.2.03

H89 Screen dump - CP/M 2.2.04

H89 Screen dump - CP/M Setup Disk

Last updated: 08/24/2010.

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If you have any question or comments, or if you have any old Heathkit equipment or software available, please contact me at: mark (at) garlanger (dot) com