The Apple-1 Software Library Beta

Browse all the Apple-1 programs that ever existed. A tribute to history and their hackers.
Run them in any emulator, or instantly on the (real) machine.

Hellorld!

by Bobby Nijssen in 2024

An alternative hello world program, a contribution to madness, all started by David (Usagi Electric).

machine codewithin 4k

History

This looks familiar if you follow the Usagi Electric YouTube channel.

Here, the presenter David Lovett was restoring a Centurion minicomputer and by mistake he ended up with Hellorld! on his display. This then took on a life of its own. He keeps a GitHub record of all Hellorld!-programs running on several vintage computers and devices.

The Apple-1 was still missing out on this, so here we go.

Instructions

The following 29 byte machine code is entered at memory location 0300:

A2 00 BD 13 03 20 EF FF E0 0A B0 04 E8 4C 02 03 4C 1F FF 0D 48 45 4C 4C 4F 52 4C 44 21

The last 10 bytes of the program are ASCII data containing a carriage return and HELLORLD!.

The program uses register X to walk these 10 characters and display them on the screen. Let's break the program down:

Address Bytes Instruction Explaination
0300 A2 00 LDX Load 00 (zero) into register X.
0302 BD 13 03 LDA Load memory location 0313 + X into register A.
20 EF FF JSR Jump to Wozmon ECHO character subroutine. This reads register A and echo's it to the screen.
E0 0A CPX If X is 0A (= 10 characters), then carry is set.
B0 04 BCS Branch if carry is set and go 4 bytes forward.
E8 INX Increment X by 1.
4C 02 03 JMP Jump to 0302.
4C 1F FF JMP Jump to FF1F, back to Wozmon.
0313 0D Data Carriage return (ASCII).
48 45 4C 4C 4F 52 4C 44 21 Data HELLORLD! in ASCII.

The 6502 Quick Reference gives an overview of the 6502 instruction set and helps in understanding the above.

References

Screenshot of Hellorld!

Historical reference : hardware

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 code of the monitor program.

The Apple-1 Computer main board
The Apple-1 Computer main board.

The 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.

The Apple-1 Cassette Interface or ACI
The Apple-1 Cassette Interface or ACI.
Cassette with Apple BASIC
Cassette with Apple BASIC.

Software

Its BASIC was written by Woz himself. It did not support floating point arithmetic, but was tiny enough to fit in 4K of memory. 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.

How to emulate?

It is easy to run the software with one of these emulators:

View a comparison of emulators here.

...and run a program

First, start the emulator of choice and have it run Wozmon (or BASIC), then use the Wozmon button to copy-paste the program code into the emulator.

For example: open Apple 1js in another browser tab. Hit CLS to clear the screen and RESET to enter Wozmon. Then paste the copied Wozmon code from this website.

In-website transfer to an Apple-1 Order now!

This website can connect directly (and locally) to the Keyboard Serial Terminal from 8BitFlux.com. It uses the Web Serial API for this and is supported by Chrome or Edge browsers. The Wozmon code of any program can be transferred quickly.

The Keyboard Serial Terminal connected to an Apple-1
The Keyboard Serial Terminal connected to an Apple-1.

Use the Serial button to transfer the current program to the Apple-1. For example, BASIC takes around 20 seconds to transfer at a speed of 57.6 kbps. The board is compatible with the higher-speed TurboType™ format (with CRC check).

After the transfer of the game or program, switch over to the normal Apple-1 keyboard (by pressing a button) and enjoy it. This makes also a great kit for museums and public events. Kits available now »

Further exploration


Credits

This library is an initiative of 8BitFlux.com. It can be put to full use with a Keyboard Serial Terminal adapter board, which let you run software instantly on a (real) Apple-1.

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 emulators. The hobby computer enthusiasts of the past, but also people of the present, who keep this hobby so alive. Thank you all.

Disclaimer

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.

Mistakes happen, as this website is not generated by any AI, please report any nonconformities.

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