The Tempest Mystery

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JohnsBargs
Posts: 169
Joined: Fri Oct 19, 2018 2:22 am

The Tempest Mystery

Post by JohnsBargs »

Something incredibly weird is going on, and I don't know what.

I've been fiddling around tweaking my colour mod of Tempest, and I also wanted to make a monochrome inverse one representing how the game could have looked when it was released in 1981. And then I noticed something really odd. Here are screenshots of my latest builds, one colour and one mono. See if you can see what's strange about them:

txc1.jpg
txb1.jpg

Did you spot it? One of them says "PRESS FIRE KEY" and the other says "PRESS ANY KEY", with an untidy extra space on the end of the line.

But here's the mad thing: both of them were made from the exact same P file. It's the only one in my Chroma folder. They were made just minutes apart. And when I go back and look at my previous builds of the last couple of days, all the colour ones say FIRE and all the mono ones say ANY.

And it's weirder still. If you go here:

http://www.zx81stuff.org.uk/zx81/tape/Tempest

and play the online browser version, it says FIRE. But if you actually download either of the game files on the page (the P or the TZK) and run them in EightyOne, they say ANY. I've scoured my hard drive and found nine versions of the P file, all of which say ANY.

What the bejeesus is going on here? Where in God's name has the FIRE version come from? Can anyone somehow extract it from the TZX? The attachment below contains my original P file, my latest colour and mono builds, and their respective COL files. I'm totally perplexed.
Attachments
TempestChroma.zip
(8.18 KiB) Downloaded 191 times
Fruitcake
Posts: 346
Joined: Wed Sep 01, 2010 10:53 pm

Re: The Tempest Mystery

Post by Fruitcake »

The inlay for the game says:
Tempest.gif
Tempest.gif (10.32 KiB) Viewed 2647 times

And this thread provides some details on how the Mikrogen joystick interface is read:
viewtopic.php?t=860#p8527

Why I try the game with and without Chroma in EightyOne, both show "PRESS ANY KEY" so Chroma is not conflicting with the IO port used to read the joystick interface.

Do you have ZON-X sound enabled in the emulator you are using? One version of the interface uses the same IO port as the Mikrogen joystick interface.
JohnsBargs
Posts: 169
Joined: Fri Oct 19, 2018 2:22 am

Re: The Tempest Mystery

Post by JohnsBargs »

I solved the problem yesterday - setting the 8K-16K memory option in the emulator to RAM magically makes "FIRE" appear. I can only assume this is something to do with it thinking it has a joystick plugged in.
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