David Haywood's Homepage
MAME work and other stuff

Tiny Alien Invaders

November 18, 2014 Haze Categories: General News. 13 Comments

Thanks to CPZ the site theme is now looking more like it used to look before and feels like home once again. In the meantime there have been a couple of new developments, but the one that caught my eye most was the discovery of a unique Space Invaders variant called ‘Alien Invader’

An external contributor ‘Seth Soffer’ discovered a Space Invaders game running on a tiny bartop cabinet using a 6502 CPU. He provided the following pictures, and a rom dump.


Alien Invaders
Alien Invaders Alien Invaders

There are a few things that stand out here, first of all the 6502 CPU, meaning it’s definitely not running Taito Space Invaders code, that used an 8080 CPU. Second of all, the cabinet, it’s tiny, as is the display (which is black and white with a colour overlay attached to the screen)

The manufacturer of this unit is unknown, we’re told the PCB is etched with ‘Forbes’ so that’s our best guess. When it was manufactured is also unknown, externally it manages to look almost like some retro-contemporary item, but chances are it’s not much newer than the original Space Invaders.

Emulation also highlighted something else that you can maybe tell from the original photos. The screen resolution is very low, 128×128 pixels, something you’d associate more with a handheld device than an arcade machine. I did some of the emulation work, although the game jumped off into the weeds as soon as you generated an interrupt, Mariusz Wojcieszek noted that by simply returning in such a situation the game would run fine, so it’s possibly some kind of protection (Kale speculates that it’s a PROM) Maybe there is some other purpose to jumping there, like the address bus bits signalling some other hardware, I’m not sure. We could probably do with some clear PCB pictures to see what’s there to either confirm or rule out various theories.

The sound isn’t emulated, again we don’t know what generates it at this stage, could be discrete like the original Space Invaders, but without further PCB images I really don’t know.

Unlike Taito’s Minivader (which was actually just a cabinet test board) I think this was intended as a full ‘for arcade use’ game, the tiny resolution actually makes it more of a Mini-vader than Mini-vader itself tho :-) The game plays well and is a respectable effort to file with the other odd releases based on Space Invaders using unexpected hardware. (I think the only other one with a 6502 is ‘Attack UFO’ but that again is very different hardware, AFAIK based on similar hardware to the Commodore home systems)

Anyway, here are some screenshots of Alien Invaders running, the colour overlay positions are guessed based on the screenshots


Alien Invader Alien Invader Alien Invader Alien Invader

Alien Invader Alien Invader Alien Invader Alien Invader

Thanks again to Seth Soffer for this contribution, and if you’re reading, more PCB info / high res pictures would really be appreciated :-)

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Site Layout

November 8, 2014 Haze Categories: General News. 51 Comments

In response to the security issues a few things were updated here, including the site theme, which I was unable to update before because the site was using an older version of PHP. It does however appear that the new version of this theme looks nothing like the old version, and doesn’t really work properly with some things on the site. So far I haven’t actually found a single layout I like as much as the older one here, which was neat and unintrusive when it came to the style and layout of my pages (even if the new one is probably more technically correct from a CSS usage / enforcing CSS usage point of view)

As a result I’m going to end up having to do a bit of CSS hacking until I have something I’m happy with again, and also figure out a way to stop it only showing previews of posts (I’ve got WP set to display full text, but it seems to ignore that)

In other words, please be patient while I get everything looking like it should ;-)

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Admiring The View

November 6, 2014 Haze Categories: General News. 17 Comments

One thing that has been on my ‘to look at list’ for a while is Race Drivin’ Panorama, a special 3 screen version of Race Drivin’.

Hard Drivin’ / Race Drivin’ alone is a bit of an insane hardware setup, and Race Drivin’ Panorama makes that even crazier by adding 2 extra slave video PCBs to drive each monitor (based on the lower resolution ‘Compact’ releases, using a standard monitor for each of the side views as opposed to the medium res one used by the center view)

Luckily as MAME’s device model has improved and more and more code has been converted to a device structure it has become easier to support multiple video boards etc. without having to duplicate large amounts of code or worrying about shared global variables etc. so I decided to take another look at this. As it happens there was actually one part of all of this that hadn’t been converted to a device yet, the Slapstic, and because we have more than one of them on this setup that was actually something, to my surprise, I had to upgrade.

Anyway, after doing all that, including converting the video PCBs etc. to act as devices and hooking up the serial connection between the boards (which was remarkably easy) we end up with the following


Race Drivin' Panorama
Race Drivin' Panorama
Race Drivin' Panorama
Race Drivin' Panorama
Race Drivin' Panorama

It’s actually playable (albeit very slow, it has rather a lot of CPUs)


Race Drivin' Panorama

Unfortunately there’s what I’m starting to strongly suspect is a MAME core bug causing partial updates to not quite work properly on everything except the primary screen, you can swap the order of the screens and the primary screen (be it a side screen or the main view) will always render correctly, but the other screens will only partially update the display, usually in the wrong places, causing those displays to stutter and appear incorrect frequently. There doesn’t seem to be any use of the ‘first_screen’ in the driver code, so I strongly suspect it’s something core level causing the issue. Fingers crossed somebody can help track that down, and this will be fully playable!

*edit* I’ve managed to find a kludge around the display update issue, however upon further testing the side-screens crash if you select the Roadster car. According to real hardware sources the game should display a full 3d view rather than the car panels at the sides for that car, which is probably related (the GSP seems to time out loading pictures in MAME, when I guess it should simply fail to load them because they’re not present?) I’ve put up a video of the thing in action here, although the sound is out of sync due to MAME not liking it when you record multi-screen games with dyanmic refresh rates ;-)

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Hikaru Arisa Michiyo Miho

November 3, 2014 Haze Categories: General News. 39 Comments

It’s about time for an update here anyway, I’ve been delaying it for a while, but one piece of recent news has come to my attention that is worth a more immediate piece of coverage.

The last two years could easily be dubbed as ‘year of the prototype’ with a number of very rare and interesting discoveries being made.

Unlikely locations seem to be the key to finding a number of these, and it was announced yesterday on the neo-geo.com forums (registration required) that a group of members there had aquired a rare Sega prototype on System 18 hardware. Where was this located? Portugal of all places.

The members in question, and whom I offer my greatest thanks to are
Atro (aka Rui Baptista)
_rm_ (aka Ricardo Marques)
and
1up (aka Daniel “casebres”) who purchased the board in question

The board was found in a collection of other dead PCBs that had simply being left to rot in a warehouse / were intended for use as parts. After negotiating with the owner of the boards a number of them were purchased by ‘1up’. One of the boards in that purchase was a Sega System 18 board. The motherboard was dead and in a very poor rusted condition – completely non-functional, but by transferring the unknown ROM board to a working System 18 motherboard (owned by _rm_) a great surprise was unveiled. They recoded some videos of their findings here and here. A thread was also posted about it on the shmups forum, which is where it caught my eye.

Anyway, the ROM board was from the Sega / Santos prototype ‘Hammer Away’. A vertical shooter or ‘shmup’ that was set to be released around 1991 but ended up being cancelled for unknown reasons.

Things moved quickly from there, the ROMs were dumped and sent to ‘system11′ who forwarded them to the development team for us to look at. Interestingly it turned out the game used twice as many tile as any other System 18 game (requiring custom handling) and additionally required the YM chip to generate an interrupt to drive the sound – something that had been hooked up in some Sega drivers but not the System 18 one. With these issues fixed it booted.


Hammer Away Hammer Away Hammer Away Hammer Away Hammer Away

Interestingly the only previous record of this game was of it being exhibited at the AM show in ’91. Unmamed has had some screenshots of this for a while, although interestingly they’re from a different revision to the one found. At no point does the dumped game show the additional text on the title screen under the logo, nor does the title screen ever have a black background. This data seems to be in the tile roms, but is unused, maybe the version found is a later build with it removed.


Hammer Away

The Santos connection is another potentially interesting one, it is possible, but not confirmed that this is the same Santos who developed the Playstation titles ‘AirGrave’ and ‘Stahlfeder’. It is also unknown if the ‘Santos’ has any connection with the country in which this board was found – it is a common name in Portugal, but that could just be coincidence. (According to hap it is most likely ‘MegaSoft’ who also went by ‘Santos’ and ‘Whiteboard’, see http://segaretro.org/Megasoft )

The ROM Test in service mode fails in MAME, but I think that’s just due to the game being a prototype, we see it for a lot of them. (edit: confirmed, the 4 program roms it checks fail the check on real hardware too, so not a MAME bug or a dump problem)

As for the game, it uses a ground / air based attack system (something that the likes of Xevious had made popular) and is played over 5 stages. I’ve only played through one loop, so I’m not sure if it loops forever or gives a credit sequence later. There are no real bosses to speak of, and it feels older in terms of game mechanics than the 1991 date would suggest, possibly why it ended up not being released – by that point the likes of Raiden had really changed what people expected from the genre. These days it’s a lot easier to judge things as a game, rather than looking at release years tho. Below are some more screenshots taken during gameplay.


Hammer Away Hammer Away Hammer Away

Hammer Away Hammer Away Hammer Away

Hammer Away Hammer Away Hammer Away

Hammer Away Hammer Away Hammer Away

Hammer Away Hammer Away Hammer Away

System 18 games are always interesting to study from an emulation point of view due to their use of the Genesis VDP – in some cases it was used almost like a protection device (and when bootleggers did bootleg System 18 games they usually stripped out / replaced any graphics it generated) Here it is used for a number of things, including the text layer, and some sprite effects.

Again I’d like to thank Atro, _rm_, and 1up for making this possible, if you don’t look and take chances on unknown things then you don’t find treasures like this, and their generosity means it will now always be a remembered game, rather than a forgotten one, it has literally been brought back from the dead.

This post I’ve made here just summarizes events, I suggest you register and read the original pages too.

(Note, if you get requests in your browser to install some driver / plug-in when browsing my site DO NOT DO IT. Apparently something has infected the host here, but it’s very selective about who it targets and a pain to track down. I’ve elevated the concern, but I can’t tell you if / when it’s fixed for sure because I’ve never seen it first hand. This I believe applies to ALL emulab.it sites because people have been reporting similar with Kale’s blog. Keep your adblockers in use, and browsers / Flash plugins etc. up to date)

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Moving to Github

October 20, 2014 Haze Categories: General News. 18 Comments

A number of you have probably noticed the old GIT mirror being up and down over the last few days, that’s because there’s been a fair bit of movement going on under the surface.

As per the announcement on mamedev.org the project is now officially being developed on Github, as opposed to our own inhouse operated SVN server. You can still pull the source exactly as before using your SVN client (tortoiseSVN or whatever you choose on Windows) but using the new address listed there instead of the one you’ve used in the past.

You can also update to a GIT based client for added functionality. The web based interface Github provides can be browsed like the GIT mirror, although there are currently some limitations imposed by GitHub (files per folder) that may cause some issues.

The old SVN server is now set to read only for everybody and will no longer be updated.

I don’t really have much to add to the announcement at this time, but feel it’s important to spread the message.

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UME 0.155

October 15, 2014 Haze Categories: General News. 52 Comments

UME (logo by JackC)
UME is the complete/combined version of the MAME / MESS project.

Official whatsnew texts for (MAME, MESS) provide full details of what has changed since 0.154, much of this has been covered in my ‘ex’ updates.

UME 0.155 Windows binaries – 32-bit, 64-bit and all tools
(source matches official mamedev.org source distribution)

Other Binaries (if you don’t know what these are you don’t need them)
MAME/MESS split 0.155 Windows binaries – 32-bit, 64-bit and all tools

Points of Interest

Not a great deal has changed from a user-visible point of view since the last ‘ex’ build, but I’ll cover some highlights, and anything interesting I missed from the entire cycle soonish.

One thing I was looking at shortly before the release is a Mario Bros. bootleg. Most bootlegs are quite dull, often changing nothing of note, or offering a significantly degraded experience. This Mario bootleg was said to be on ‘Ambush’ hardware by dumper Tirino73 and while some things differ enough to make me wonder if it’s really an Ambush board the sound system and a number of other details do seem to fit that profile quite well.

That’s what is most interesting about this bootleg, the sound. Right now in MAME the original Mario has terrible sound, the walking effect is far louder than everything else, and it need some serious attention by somebody more knowledgeable about discrete sound hardware than myself. This bootleg however has a completely different sound system to the original, utilizing 2 AY8910 chips for sound effects and music. If that wasn’t interesting enough the bootleggers based the melodies on Donkey Kong Jr, but they didn’t just rip things directly because Donkey Kong Jr. doesn’t use AY8910 chips either so it’s clearly been reworked for this hardware.

There was also a Donkey Kong 3 bootleg on basically the same hardware. Unfortunately when these were dumped the colour PROMs were not dumped at the same time, and it’s unlikely they’re meant to be 100% the same format as the originals, this has made progress on the emulation slower. I’ve uploaded a video of the Mario bootleg which you can watch below, the Donkey Kong 3 bootleg is currently in a worse state.



Frisky Tom is an interesting little game too, previously we had 2 sets in MAME, the parent set, which is presumed to be a World release is the most polished of the two, it has a full attract demo cycle showing gameplay, it shows the game level ‘Rank C’ before each round, it calls the player lives ‘TOM’ in test mode, and represents them onscreen with a little icon showing your guy in the top left corner. It’s also censored, because the game is actually an ‘adult’ game, believe it or not (probably easy enough to believe, it’s from Nichibutsu)


Frisky Tom Frisky Tom
Frisky Tom Frisky Tom

The other version in MAME was an older version, it’s uncensored, it lacks a full attract demo, or the level display, and uses a water tank icon for the player lives, calling them ‘TANK’ in test mode (which until you realise means water tank, is a little confusing)

Frisky Tom Frisky Tom

Just before 0.155 Andrew Welburn dumped another set of the game, and it seems to be an even older set. One interesting thing about this game is that the graphic roms differ slightly between revisions, obviously in part due to one set having censored graphics, and the other not, but also details live the lives counter icon previously mentioned.

There were two things of note with this new set, first of all the tile the contains the lives counter symbol on the previously mentioned sets is a blank tile, second the part of the main CPU rom that the protection MCU runs is encrypted (all sets of the game use a weird setup where the protection CPU just runs code from the main CPU, more like a sub-cpu than a protection cpu) This was a simple bitswap on the opcodes only, but is still an interesting difference. Once that was all figured out and the game booted it was clear why the lives counter tile was blank, this set, instead of using a symbol in the corner, uses a graphic near the high score text made from existing tiles, indicating it’s probably an earlier set than either of the previous two.


Frisky Tom

It’s always nice when new clones have actual visible differences, especially like this where it gives a snapshot into how the game was refined over time.

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