David Haywood’s MAME(tm) WIP

It’s always nice when something from outside the development team is submitted when you’re least expecting it, especially when the submission is of a good quality and is something we’ve considered to be very difficult to work on.

Tonight that’s exactly what happened, ElSemi passed along some code to me from a contributor in China known as “XingXing”

The code was to simulate the protection in the PGM game “Puzzle Star”, another one of the Mysterious PGM games which never appeared on the IGS site when most of the other titles were up. It’s a puzzle game, very similar to Mang-Chi which was emulated a few days ago but with some extra twists (involving the stars, combos, and ‘promotions’). There may be one or two problems with the simulation, but for the most part it seems to work correctly.

I’ve uploaded some resized screenshots you can see below so people can get a good idea of what this PGM cart looks like should they wish to buy it.

Please note, once again this is _not_ my WIP, I’m just commenting on a very impressive external submission. Its easy to be critical of low quality external submissions, or people not being willing to fix things, but always very pleasing to see quality external submissions like this one.

It amazes me sometimes how much users of MAME moan and complain about certain bugs, when if they simply put a fraction of the effort they do complaining into trying to fix the bug then they’d almost certainly be able to fix it.

Mysterious Stones has been broken since around MAME 0.77u2. There are a few bad tiles near the start of the first levels, and by the 2nd level it’s apparently unplayable.

I took a quick glance at the vidhrdw/mystston.c file in MAME and saw the following code.

WRITE8_HANDLER( mystston_videoram_w )
{
    if (videoram[offset] != data)
    {
        videoram[offset] = data;
        tilemap_mark_tile_dirty(fg_tilemap, offset & 0×3ff);
    }
}

WRITE8_HANDLER( mystston_videoram2_w )
{
    if (videoram[offset] != data)
    {
        mystston_videoram2[offset] = data;
        tilemap_mark_tile_dirty(bg_tilemap, offset & 0×1ff);
    }
}

the error stands out a mile, even if you’re not a programmer an error like that shouldn’t be too hard to fix. The mystston_videoram2_w handler is broken. As an optimization the code is meant to check if the contents of videoram is the same as the value being written to it, and then only write it if it isn’t the same. The mystston_videoram2_w handler is checking the wrong video ram. The bug was obviously introduced as the result of a simple copy & paste error.

fixing the bug simply involved changing

if (videoram[offset] != data)

to

if (mystston_videoram2[offset] != data)

in WRITE8_HANDLER( mystston_videoram2_w )

A _very_ simple one line fix. The source is available so people can make fixes like this.

Thanks to The Mame Italian Forum Guys, who are by far the quickest and most reliable when it comes to dumping simple PCBs if you need some help with your boards, Afega’s Mang-Chi is now supported in the afega.c driver. It’s a game very similar to Honey Dolls, but from what I can see, without the adult content.

ElSemi has been working on emulating the protection in “The Killing Blade” a game running on the PGM platform, and I’ve been porting his findings into MAME.

The Killing Blade was always a very mysterious game, near impossible to find any information on the only real information lay in the depths of the Taiwanese section of the old IGS site with only 2 tiny screenshots which weren’t even clear enough to determine what type of game it was.

Anyway, so that any potential buyers of the game actually know what they’ll be getting I’ve decided to take a few snaps of it. It’s a Samurai Shodown style game, quite bloody, with some nice effects. It’s a tag game like some of the CPS2 titles, but in this case both characters share a single energy bar. The characters and moves are more interesting than in a lot of similar titles, although the animation and quality of some of the graphics lets the game down a bit.

The game may not work 100% correctly yet as there are still some very suspicious things going on with the protection and more than a few things that don’t make much sense yet.

I’ve also added sprite zooming to the PGM driver, although this has slowed it down quite a bit for now. I may re-optimize it later, the PGM sprite system is messy to support.

Before anybody asks, No, I don’t plan on looking at the newer titles or porting ElSemi’s KOV2 work to MAME. I feel it’s more important to get the older IGS titles sorted out before even thinking of looking at the newer ones like Martial Masters, Knights of Valor 2, DoDonPachi 2 etc.

Note, these screenshots have been resized to look better on a standard display because PGM uses a strange 448×224 resolution.
Note 2, this is really ElSemi’s WIP as porting his code to MAME is trivial compared to figuring it out in the first place.

Anyway, now everybody has a pretty good idea what it looks like.

I can only assume they were talking about their own game. The ‘Level Select’ screen doesn’t seem to let you actually select anything apart from Level 1, and the High Score table seems rather broken… Assuming those aren’t emulation bugs they are pretty ridiculous :-)

Anyway, I’ve fixed the background colours, although the game does appear to have a severe identity crisis, it doesn’t seem to know if it wants to be Tumble Pop, or Bubble Bobble. You suck thins up with your laser gun, but when you shoot the enemies they turn into bubbles.

The PIC was read-protected so no sound for now.

Note the High Score table (which doesn’t even work properly) still has DECO in it.