CreatiVEmu Forum

What a amazing great picture

Another day, another game working!

Hi all - can you please reword/explain how this works?
You load the GPL like it was a normal ROM (such as the Basic interpreter) saved on SD, right?
And then how do you load the games? From cassette tape/audio file?
Or does the ROM contain GPL and the collection of games with an in-game menu to choose the one to execute?

To use these, just extract the zip file to the root of your SD card - which will create a GPL folder with the required ROMs, patches and cvgpl.bin

Load the cvgpl.bin ROM through MegaSDCart menu.

For now, the CV ROM contains the menu to load and patch each game.

TI99 keys are

E - Up, S - Left, D - Right, X down, Q - fire.

6 - Proceed, 9 - Back

Joystick1 is available where the game uses it.

Tom and Mega are currently testing the TI PEB drive module emulation - which will bring all 12 Scott Adams adventures with progress saving, only on the MegaSDCart.

The "dark mode" Wumpus and Car Wars came from me spending too much time watching Youtube videos of the TMS replacement chip where the users were changing the palette on the chip - which made me think - why not just patch the ROM?

Thanks for the explanation.
If I run the .bin on emulator instead, it just shows the menu but is unable to load any files. I understand this is different when running on MegaSD, and the bin is able to "hook" the correct files.
It is a very clever system indeed!

Here's a couple of emulator files.

For Salora Manager, run creativision -3 -c wumpus.cas then just type CRUN.

For creatiVision, run creativision -r wumpus.bin -g

Enjoy!

Gosh it works like a charm!!
The gameplay is very similar to Mattel's "Dungeons and Dragons" and "Masters of Universe" handheld - that I simulated back in 2001 ( http://www.madrigaldesign.it/sim/download.php#sect4 )

BASIC Color Character Sets

I thought it may be worth while to copy a BASIC demo to GPL, just to do a performance comparison.

COLOR 0 is the background colour, VDP register 7.

However BASIC always sets it to foreground Transparent, Background colour.

So COLOR 0,2,2 would give VDP Register 7 == 01

Now the real fun begins!

Chapter 13 shows the character sets as 1 == 01-07, 2 == 8-15, 3 == 16-23 and so on.

This is inline with the VDP colour table documentation.

However BASIC likes to confuse things a little.

COLOR 1,2,2

This would make you expect colour table entry 0 (1 for BASIC) to be set to $11.

So BASIC uses colour codes 1 through 16, which is 4 bits 0 through 15.

The BIG fly in the ointment is that COLOR 1 maps to colour table entry 21!!

BASIC uses the following formula to determine which colour table entry to update.

For COLOR 1,2,2

Take COLOR 1
Decrement
Add 20
And 31

This puts COLOR1 at the 20th entry in the colour table!!

The AND 31 ($1F) just ensures it wraps correctly, when added to colour table base address.

Some investigation shows that BASIC sees ASCII32 as Pattern table entry 192 ($C0).

By subtracting 32 from 192, you get entry 160 - which is colour table entry 21. Subtract 1, as the table in VDP is zero based - and you find the magical 20

This GPL was a cool thing on the TI. I also find the cpu interesting, the changeable workspace, some interesting functions.

OK - here's a minimal graphics example from http://www.madrigaldesign.it/creativemu ... xample.zip converted to GPL.

A nice little goldfish