Altair 8800 Emulator

A MITS Altair 8800 emulator that runs in the terminal. Capable of booting CPM 3 from 8" floppy disk.

Emulated Devices:

• Intel 8080 CPU
• 88 2SIO - Serial IO Board
• 88 DCDD - 8" Floppy Disk Controller (329K .dsk)
• Teletype Terminal - (Connected to port A 2SIO)

Usage

Syntax:

altair.exe -o<offset> <rom> -d<letter>:<disk_path>

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Options	Desc	Default
-o<offset>	Offset	0x0000
-r<size>	Ram size	0x8000 (32K)
-d<letter>	Floppy Disk Img (A - P)

• Offset should be in hex
• Programs are deposited into memory sequentially starting from -o<offset>

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Booting From Floppy Using Disk Bootloader (DBL) ROM

• Code is required to boot off of a floppy disk.
• Download Disk Bootloader (DBL), 88dskrom.bin
• Load Disk Bootloader (DBL) at FF00 eg -oFF00 88dskrom.bin
• Load a bootable 8" floppy disk file (329K .dsk) into A drive -dA:

altair.exe -oFF00 88dskrom.bin -dA:<bootable_disk_file>

ROMS

Load Offset	Filename	Description	Link
FF00	88dskrom.bin	Disk Bootloader (DBL)	https://github.com/tommojphillips/Altair8800/tree/master/roms
F800	altmon.bin	Altair Monitor	https://github.com/tommojphillips/Altair8800/tree/master/roms
FD00	turnmon.bin	Turnkey Monitor	https://github.com/tommojphillips/Altair8800/tree/master/roms
D000	wozmon.bin	Wozmon for i8080	https://github.com/tommojphillips/Wozmon-i8080/
E000 E800 F000 F800	8kBas_e0.bin 8kBas_e8.bin 8kBas_f0.bin 8kBas_f8.bin	Altair Basic 8K ROM	https://altairclone.com/downloads/roms/8K%20BASIC/

8" Floppies 329K .dsk

Filename	Description	Link
cpm22b23-56k.dsk	CPM 2 v2.2b	https://altairclone.com/downloads/cpm/CPM%202.2/CPM%202.2B/
cpm3_v1.0_56k_disk1.dsk	CPM 3 v1.0	https://altairclone.com/downloads/cpm/CPM%203.0/
zork.dsk	Zork disk	https://altairclone.com/downloads/cpm/CPM%202.2/Zork/
Disk Basic Ver 4-0.dsk	Disk Basic 4.0	https://altairclone.com/downloads/basic/Floppy%20Disk/
Disk Basic Ver 4-1.dsk	Disk Basic 4.1	https://altairclone.com/downloads/basic/Floppy%20Disk/
Disk Basic Ver 5-0.dsk	Disk Basic 5.0	https://altairclone.com/downloads/basic/Floppy%20Disk/

Altair Basic 8K ROM

altair.exe -oE000 8kBas_e0.bin 8kBas_e8.bin 8kBas_f0.bin 8kBas_f8.bin

WOZMON, ALTMON, CPM 3 8" Floppy (329K .dsk)

Boots into wozmon.

• type FF00R to boot cpm3 from floppy
• type F800R to jump to Altair Monitor

altair.exe -oFF00 88dskrom.bin -oF800 altmon.bin -oD000 wozmon.bin -dA:cpm3_disk1.dsk -dB:cpm3_disk2.dsk

Building

The project is built in Visual Studio 2022

1. Clone the repo

   git clone --recurse-submodules https://github.com/tommojphillips/Altair8800.git
   

2. Open vc\Altair8800.sln in visual studio, build and run