This document describes the first internet game developed for the Commodore 64 home computer. The game, called Artillery Duel, is a turn-based online multiplayer game that uses a peer-to-peer network protocol over UDP. It was created to demonstrate internet connectivity on the Commodore 64 using an assembler-written TCP/IP stack. The game and its source code are available to download so others can play and participate in online matches.

1. Artillery DuelArtillery Duel .net.net
The first Internet game for the Commodore 64The first Internet game for the Commodore 64
Leif BloomquistLeif Bloomquist
Toronto PET Users GroupToronto PET Users Group
World of Commodore 2006World of Commodore 2006

2. TCP/IP Stacks for the C64 in Machine LanguageTCP/IP Stacks for the C64 in Machine Language
Services
TCP
DNS DHCP Echo
Transport UDP ICMP
Network IP
Addressing ARP
Ethernet driver CS8900A / LAN91C96
Ethernet interface RR-Net / TFE / ETH64
Green: Working Yellow: Partial Red: Unimplemented
Image courtesy Per OlofssonImage courtesy Per Olofsson
IP65 – ca65 cross-assemblerIP65 – ca65 cross-assembler
Netlib64 – DASM cross-assemblerNetlib64 – DASM cross-assembler

3. Internet ProtocolsInternet Protocols
Transport Control Protocol (TCP)Transport Control Protocol (TCP)
Guaranteed delivery of data + packet orderingGuaranteed delivery of data + packet ordering
Not implemented in ML yet, high overheadNot implemented in ML yet, high overhead
A lot of work for a poor 1Mhz computerA lot of work for a poor 1Mhz computer
User Datagram Protocol (UDP)User Datagram Protocol (UDP)
Much simpler protocol than TCPMuch simpler protocol than TCP
No guarantees – you do all the confirmationNo guarantees – you do all the confirmation
Working implementations in 6502 MLWorking implementations in 6502 ML
Used extensively in PC Internet gamingUsed extensively in PC Internet gaming

4. Network Apps for the C64Network Apps for the C64
Network apps so far have focused on utilities:Network apps so far have focused on utilities:
Web Browsing / Telnet etc. (Contiki)Web Browsing / Telnet etc. (Contiki)
Disk/Program Transfer (Warpcopy64)Disk/Program Transfer (Warpcopy64)
Terminal Software (GuruTerm)Terminal Software (GuruTerm)
Remote debugging (CodeNet, UDPSlave)Remote debugging (CodeNet, UDPSlave)
Where are the games?Where are the games?

5. Simplifying Assumptions for First AttemptSimplifying Assumptions for First Attempt
Turn-based game, not timing criticalTurn-based game, not timing critical
No central server – peer-to-peerNo central server – peer-to-peer
Only one packet “in flight” on network atOnly one packet “in flight” on network at
any one timeany one time
Minimal game “world” and playMinimal game “world” and play

6. GameLogicFlowchartGameLogicFlowchart

7. Very Simple ProtocolVery Simple Protocol

8. Where to get the GameWhere to get the Game
Grab a copy on disk from me todayGrab a copy on disk from me today
Download latest version fromDownload latest version from
www.petscii.comwww.petscii.com forumsforums
(Network Game Development section)(Network Game Development section)
Look for opponents on the #c64friends IRCLook for opponents on the #c64friends IRC
channel (channel (www.c64friends.comwww.c64friends.com))

9. Credits:Credits:
Leif Bloomquist – Game codeLeif Bloomquist – Game code
Oliver VieBrooks – Network library codeOliver VieBrooks – Network library code
Thurstan Johnston – TestingThurstan Johnston – Testing
Raik Picheta – MusicRaik Picheta – Music
Also thanks to Dustin Chambers, Robin Harbron forAlso thanks to Dustin Chambers, Robin Harbron for
ideas and assistanceideas and assistance

10. Demo Time!Demo Time!