TIKI RIVER RAID

A River Raid clone for the TIKI-100 computer, written in C and Z80 assembly.

NOTE: The game is not bug-free, but playable. You are welcome to contribute by fixing bugs or improving the game.

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Quick Start

The easiest way to play is with the included emulator on Windows:

1. Launch tikiemul.exe — then load the dsk/work.dsk floppy disk image file
2. Select O TIKIRR from the TIKI-menu to start the game

Running on real hardware

The dsk/work.dsk image is a standard TIKI-100 400K floppy format and can be used on a real machine:

• Gotek floppy emulator: Copy the .dsk file to a USB stick and load it as a virtual floppy on the Gotek connected to the TIKI
• Real 400K floppy: Boot the TIKI-100 from the Gotek, then use the built-in RÅKOPI program to copy the disk image to a physical 5.25" floppy disk
• You can also use a serial connection to the TIKI and use a transfer program (Kermit) on the TIKI, but this I have not tested

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The TIKI-100

The TIKI-100 (also known as the Kontiki-100) was a Norwegian Z80-based microcomputer manufactured by Tiki Data in the mid-1980s. Designed primarily for the Norwegian education market, it was widely deployed in schools across Norway and became one of the most common classroom computers of its era.

Specifications

CPU	Zilog Z80A @ 4 MHz
RAM	64 KB (banked, shared with VRAM)
Display	Multiple graphics modes; Mode 3 = 256×256 pixels, 16 colours
VRAM	32 KB, bank-switched into the lower 32K of address space
Sound	YM2149 / AY-3-8910 PSG — 3 channels
Storage	Dual 400K 5.25" floppy drives
OS	TIKO - CP/M 2.2 compatible, with custom ROM

Despite being a CP/M machine, it had surprisingly capable graphics and sound hardware for its time.

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The Game

Tiki River Raid is a vertical scrolling shooter inspired by the Activision classic. Features:

• Procedurally generated river — deterministic pseudo-random terrain that scrolls smoothly
• Fuel management — collect fuel barrels to stay airborne
• Multiple enemy types — helicopters, boats, and jets
• Bridge targets — destroy bridges to advance through sections
• Sound effects via the AY-3-8910 PSG
• Lives system — 3 lives to start

Controls

Key	Action
A	Move left
D	Move right
Space	Fire / Start
P	Pause / unpause
Q	Quit

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Building

Prerequisites

1. z88dk — the Z80 cross-compiler toolchain. Install to C:\z88dk (or adjust paths in build.ps1). The ZCCCFG environment variable should point to <z88dk>\lib\config.

2. PowerShell (included with Windows).

Build

.\build.ps1

This compiles all C and assembly sources and produces:

• build/tikirr.com — the CP/M executable
• build/tikirr.dsk — a raw 400K disk image

Additional build options:

.\build.ps1 -Clean       # Clean build outputs first
.\build.ps1 -Verbose     # Show full compiler output

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Deploying

Prerequisites

1. Djupdal TIKI-100 emulator — place tikiemul.exe in the project root (included in the repo). The emulator configuration file tikiemul.ini is included.

2. TIKI-100 system ROM — tiki.rom (included in the repo).

3. Base disk image — dsk/workbase.dsk contains the TIKI-100 OS and menu system. The deploy script copies this and adds the game executable.

Deploy and run

.\deploy.ps1

This will:

1. Build tikirr.com (if not already built)
2. Copy dsk/workbase.dsk to dsk/work.dsk
3. Write TIKIRR.COM into the CP/M directory on the disk image
4. Launch the Djupdal emulator with work.dsk on drive A:

Deploy options:

.\deploy.ps1 -NoBuild    # Skip build, deploy existing .com file
.\deploy.ps1 -NoLaunch   # Deploy to disk image without starting emulator

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Project Structure

build.ps1          Build script
deploy.ps1         Deploy script (writes CP/M disk image + launches emulator)
tiki.rom           TIKI-100 system ROM
tikiemul.ini       Emulator configuration
src/
  c/               C source files (main, video, input, river, sound, sprite)
  asm/             Z80 assembly (VRAM routines, keyboard scanning)
build/             Build output (excluded from git)
dsk/               Disk images (base image + work image)
docs/              Technical notes
img/               Screenshots

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Credits

TIKI RIVER RAID programmed by Arctic Retro (Tommy Ovesen) with the help of Anthropic Claude Opus 4.6.

Built with z88dk. Emulated with the Djupdal TIKI-100 emulator, Arctic retro version.