diverse

Reverse-engineered Intel 8080 source for ДИВЕРСАНТ ("Diversant" / "Saboteurs"), a ≈6 KB arcade-style shoot-the-paratroopers game for the Радио-86РК (Radio-86RK) home computer. The original binary is preserved as tape/DIVERSE.GAM; diverse.asm reassembles to that exact byte stream under just ci.

Play it in your browser

No emulator install required — the rk86.ru web emulator can load the tape file directly from this repo:

https://rk86.ru/beta/index.html?run=DIVERSE.GAM

Keys (matches the "instructions" screen inside the game):

• ← → ↑ ↓ — move the MX-12 anti-air platform
• Space — fire a torpedo
• АР2 (emulator: usually mapped to F5) — pause
• СТР (emulator: usually F6) — clear screen / hard restart
• Ctrl-C — return to the RK86 monitor

Main-menu letters:

• N (Начать) — start a new game
• U (Уровень) — cycle difficulty (ЛЕГКИЙ / СРЕДНИЙ / ТЯЖЕЛЫЙ)
• I (Инструкция) — show the full instructions screen

Purpose — educational, not commercial

This project exists purely for historical preservation and educational value. The Radio-86РК was a widely-cloned Soviet-era hobbyist computer built from the open schematics published in the magazine Радио in 1986, and games like ДИВЕРСАНТ were shared hand-to-hand on cassette tape. The goal of this repository is to:

• Preserve the original binary (tape/DIVERSE.GAM is the untouched tape dump — do not modify).
• Explain how an early-80s-era assembly programmer laid out a complete game under ~6 KB, using the RK86 monitor ROM, the К580ВГ75 CRT controller, video-RAM glyph codes, and self-modifying code for everything from per-difficulty tuning to the main frame-delay loop.
• Document the hardware idioms (RK86 character set, keyboard matrix, ESC-Y cursor positioning, tape format) that the game relies on, with cross-references to the authoritative monitor-ROM source.

No effort has been made to port the game to any modern platform or to redistribute its binary outside this educational context. Users who enjoy the game are encouraged to support the Radio-86РК emulator community at https://rk86.ru/.

Author & rights

ДИВЕРСАНТ appears to have been written by an author from Харьков (Kharkov/Kharkiv) — the city name is rendered as an in-game signature on the bottom row of the playfield (visible in the patch table near the end of diverse.asm, and on screen as the row 27 text). The original author is unknown to this project; if you know who they are, a pull request adding attribution is welcome.

Copyright in the original binary remains with its author. This reverse-engineered source is published under the terms of the LICENSE file in this repository for research, study, and teaching purposes only. Any redistribution that goes beyond these purposes should obtain the author's permission.

Repo layout

diverse.asm reverse-engineered i8080 source
tape/DIVERSE.GAM original tape dump (preserved verbatim)
diverse.gam build output; byte-identical to tape/DIVERSE.GAM
Justfile `just ci` = build + compare to tape
disasm.py small linear i8080 disassembler used during reversing
CLAUDE.md notes collected during reversing (hardware idioms,
SMC patterns, difficulty table)
diverse-splash.png boot screen
diverse-game.png gameplay screenshot

Building

just ci # assembles diverse.asm, diffs against tape/DIVERSE.GAM

The toolchain is asm8080 (browser + CLI Intel 8080 assembler, available on npm as asm8080), invoked via bunx. Any change that leaves diverse.gam byte-identical to tape/DIVERSE.GAM is safe — just ci will report no diff.

Further reading

• RK86 programmer's reference: RK86.md — memory map, peripherals, character set, monitor jump table, tape format.
• Monitor ROM source: begoon/rk86-monitor — the F800h..FFFFh code this game calls into (online)
• Notes gathered while reversing: CLAUDE.md — К580ВГ75 SCN4 decoding, self-modifying difficulty table, FD27h sound entry point, and other patterns encountered in the binary.