Arcade1UP: Ms. Pac-Man

Arcade1UP: Ms. Pac-Man
Developers: Namco, Arcade1UP Publisher: Arcade1UP Platform: Arcade (Arcade1UP) Released in US: 2020 This game has unused code. This game has hidden development-related text. This game has unused modes / minigames. This game has unused graphics. This game has revisional differences.

A series of Ms. Pac-Man home arcade machines produced by Arcade1UP. Models currently analyzed include:

• Ms. Pac-Man full-size machine "8220" (model 1 feat. Super Pac-Man, Dig Dug, and Pac-Mania)
• Ms. Pac-Man full-size machine "8262" (model 2 feat. Dig Dug, Galaxian, and Super Pac-Man)
• Ms. Pac-Man full-size machine "8266" and "8267" (model 3 feat. Galaxian, Pac-Mania, and Pac-Man Plus)
• Ms. Pac-Man Head-to-Head arcade table "8255"

To do: Attempt to properly find test menu. It can likely be enabled by holding down 1P and 2P buttons while turning the machine on, but this is still not confirmed. Various other pieces of unused content (READMEs for developers, numerous pieces of code, etc.). Raspbian mentions are part of the compiler ID that GNU CC (in this case 6.3.0 with Debian patches) inserts into linked object files - maybe they were using raspi for development and moved to rockchip for mass production.

Firmware Update Analysis

When the Ms. Pac-Man Arcade1UPs were first released, they...had some issues, to say the least. Arcade1UP attempted to fix the issues via downloadable firmware updates...which made things much, much worse.

On the "Head-to-Head" model in particular, installing the update would cause the screen to display in horizontal resolution; meaning, on the machine's vertical monitor, the games would play 90 degrees on their side. In attempt to make up for the drastic issue, Arcade1UP not only took down and recompiled the updates, but also added the ability to play the much-desired "speed-up chip" version of Ms. Pac-Man.

In the Arcade1UP firmware updates, all of the data is intact including the games, menu system, and various other elements of code. As such, they are basically ROM dumps of the entire machines and feature notable unused elements, as seen below.

Games Folder (data.img)

This folder contains the actual games. In the 8266 and 8267 builds, the ROMs included are only the ones for their specific menu. On the 8220 and 8262 builds, however, there are 15 total ROMs (many of which are not accessible on the actual machines):

• Dig Dug
• Dig Dug II
• Galaga
• Galaxian
• Mappy
• Ms. Pac-Man
• Pac & Pal
• Pac-Land
• Pac-Man
• Pac-Mania
• Pac-Man Plus
• Super Pac-Man
• Super Xevious
• Xevious
• NS1 (Namco System 1) BIOS

In addition, there are some separate ELF files for the games. The bottom of these files mention "Raspbian 6.3", a variant of the Raspberry Pi OS. Additionally, some of these files make reference to, and have support for, even more games in their code (though there are seemingly no ROM files relating to them). These include:

• Moon Cresta, Super Moon Cresta, UniWar S, and King & Balloon in Galaxian's file. Note that the first three games were not produced by Namco.
• The Tower of Druaga and Motos in Mappy's file.
• Grobda in Super Pac-Man's file.
• A whopping 22 games in NS1's file: Galaga '88, Dragon Spirit, Blast Off, Blazer, Dangerous Seed, Rompers, Puzzle Club (the prototype?), Quester, Quester Special Edition, Baraduke II, Berabow Man, Marchen Maze, Shadowland, Splatterhouse, Pistol Shogun, Tank Force, Boxy Boy, World Court, World Stadium, World Stadium '89, World Stadium '90, and Face Off. The only game listed in its code that was included as a ROM is Pac-Mania.

Images Folder (data.img)

This folder features the graphics for the menu system. In addition, there are some graphics that clearly relate to test menus of some type ("Key Fail/Success" screens, checksum tests, etc); it is unknown how to enable the tests on the machine itself.

Oddities

In the Ms. Pac-Man ROM, from addresses $0x57D0-$0x57FF there are three lines of blank spaces, in a pattern that does not appear in the original code. Judging by the code line preceding this area (among other factors), this is almost certainly where the secret "Hello, Nakamura!" message was in the original arcade ROM - a message that is entirely missing from the Arcade1UP data.

While a rather subtle change, its reason for removal is quite clear: this message was a key piece of evidence used in General Computer Corporation (GCC)'s initial lawsuit against Namco, which in turn resulted in GCC being granted royalties by Namco for Ms. Pac-Man products. Ironically, the Arcade1UPs are effectively the only Ms. Pac-Man product that GCC can't earn anything from, as the court ruled that "arcade machines without coin slots" are void of the royalties. Presumably, Arcade1UP and/or Namco removed the message anyway just to be safe.