Browse this growing collection of Apple-1 programs.
A tribute to history and their hackers.
Run them in the emulator right away, or just on the real machine.
Browse this growing collection of Apple-1 programs.
A tribute to history and their hackers.
Run them in the emulator right away, or just on the real machine.
by Steve Wozniak, Allen Baum in 1976
Shows the mnemonic form of the 6502 instructions that are in memory.
Sold by Apple Computer on cassette tape for $5, order code A1T008X.
In the article A 6502 Disassembler from Apple this program was published in Dr. Dobb's Journal by Steve Wozniak in 1976. At the same time Interface Age also published an article. It outlined its features and comes with the assembly source listing.
A later edition of Interface Age has an article about a search subroutine for this program. It enables the user to search for any combination of characters in an assembled program and was written by Arthur L. Schawlow.
As given by the article:
This subroutine package is used to display single or sequential 6502 instructions in mnemonic form. The subroutines are tailored to disassemblers and debugging aids, but tables with more general usage (assemblers) are included. ...
Features
Four output fields are generated for each disassembled instruction:
- Address of instruction, in hexadecimal (hex).
- Hex code listing of instruction, 1 to 3 bytes.
- Three-character mnemonic, or
???for invalid ops (which assume a length of 1 byte).- Address field, in one of the following formats.
Address format example Address Mode (empty) Invalid, Implied, Accumulator $12Page zero $1234Absolute, Branch (target printed) #$12Immediate ...
The program can be used to disassemble machine code that resides in memory. To set the begin address, the PCL ($44) and PCH ($45) zero page variables can be used.
For example, use the following Wozmon commands to disassemble the first 20 instruction of BASIC (make sure it is loaded first at E000):
44: 00 RETURN to set the low nibble of the address (E000).45: E0 RETURN for the high nibble (EO00).800R RETURN to run the dis-assembler.R RETURN run again, to displays the next 20 instructions.For more details see the article in Dr. Dobb's.
Use your keyboard to interact with this Apple-1 program.
Emulated with HoneyCrisp v1.2.7,
check here for more details.
This website has full functionality (i.e. direct serial transfer and emulation of an Apple-1) when displayed on a larger screen.
In 1976, the Apple-1 Computer was advertised for $666.66 and came with 4K of on-board memory. For a $120 extra, this doubled to 8K of RAM. The provided Operation Manual included the circuit diagram and assembly source code of Wozmon, the operating system.
The Apple Cassette Interface (or ACI) was used to load and save programs from cassette tape. The ACI Manual showed how to install it (the main board had to be jumpered correctly) and explained how it had to be used. Priced at $75, it included a cassette of Apple BASIC.
Woz wrote a BASIC interpreter by himself. It was tiny enough to fit in 4K of memory, but did not support floating point arithmetic. The software itself was free. The Preliminary Apple BASIC Users Manual explained how to write your own games and programs with it.
Cassette tapes could be bought as an original accessory to your new Apple-1. A total of nine programs were available and listed $5 each. Pick one below and go back in time.
At the time, people were also inspired by publications like 101 BASIC Computer Games. They spent their evenings and nights to key-in the games, but soon were disappointed to discover that some of these did not work at all because of the missing floating points... Arghh.
Dive deeper? Read more here and here.
The Apple-1 has a 16-bit address bus and 64kB of addressable space. Within this space the 6502-processor can use the different parts of the computer:
Woz designed a jumper area on the Apple-1 mainboard where the hobbyist-user could configure how memory should be organized. This was very flexible and made extension of the Apple-1 possible.
The full 64kB is split into 16 equal banks of 4kB each by this jumper area. The banks range from 0 to F, hexadecimal. A bank can be tied to one part of the computer: e.g. the ROM, upper RAM chips or a board in the expansion slot.
The default configuration is shown above. For example bank E (address space $E000-$EFFF) was usually tied to the eight lower RAM chips on the Apple-1 mainboard, indicated by W and the black wire in the figure. Usually BASIC was loaded here.
No windows yet. It was called a monitor program back then, the predecessor of an operating system. It allowed reading and modifying the computer's memory and starting programs. Woz his monitor was stored in only 256 bytes of ROM.
To load it, the user had to press RESET after powering on the computer. A back slash \ appeared on the screen with a flashing @ below, the cursor. Indicating the Apple-1 was ready for commands.
Try Wozmon yourself by pressing the
Run button and after that
Reset in the above emulator (any program). Then type 280 RETURN to read a memory location. Values are hexadecimal, so range from 0 to F. Change memory with 280: AB RETURN. Read it again and wow you changed memory!
Follow this excellent course to learn more. The original manual explains Wozmon as well (in Section II) and lists the assembly source code.
Use the 8BitFlux.com Keyboard Serial Terminal to connect to an Apple-1 with this website. It uses the Web Serial API locally and is supported by Chrome and Edge browsers. The Wozmon code of any program can be transferred right away.
Use the Serial button to transfer the current program to an Apple-1. For example, BASIC takes around 20 seconds to transfer, at a speed of 57.6 kbps. The board is compatible with the high-speed TurboType™ format. It also performs a CRC check and has an error LED indicator.
Done transferring the game or program? Switch the input to the attached Apple-1 keyboard by pressing a button and enjoy it. This makes a great kit for hobbyists, museums or public events. More info »
It is easy to run the software with one of these emulators as well:
This website uses the HoneyCrisp emulator. More information can be found here. It has its own software library with even more programs to explore.
View a comparison of emulators here.
An initiative of 8BitFlux.com. This website can be put to full use with a Keyboard Serial Terminal adapter board, which enables you run software on a (real) Apple-1 right away.
The textual descriptions and screenshots of the programs listed on this website are licensed under CC BY 4.0
A lot of recognition goes out to Landon J. Smith for being so kind to share his HoneyCrisp Emulator (also available on GitHub) for use on this website. Many Thanks to Uncle Bernie for his support and provision of his TurboType™ algorithm, which is part of his Apple-1 Toolchain. Last but not least, all this was not possible by all the authors of Apple-1 software and other emulators. The hobby computer enthusiasts of the past, but also people of the present, who keep this hobby so alive. Thank you all.
This website is not associated with Apple Inc. in any way.
It tries to be a tribute to (their) history. It wants to list only software that is already considered to be in the public domain, or its license permits further publication. The (online) sources of the program and other references are listed when known.
No AI is used to describe the software packages here. Human mistakes happen, so please report any nonconformities.
Made behind an 🍎 in The Netherlands.