[Conversion?] A strange Korean machine - Why not?

By muffie

Paladin (933)

muffie's picture

20-01-2009, 17:11

www.passionmsx.org/modules/news/article.php?storyid=422〈=english

"They can't easily be adapted for MSX2 as they handle differently the VDP addressing and the memory bank switching. Besides, you play them with inversion of the horizontal and vertical dimensions !"

- Besides rotating the 1084! :D, what's so difficult to adapt?
- How's the sound generated? What exactly a "z80 for sound" means?

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By hap

Paragon (2012)

hap's picture

20-01-2009, 18:36

It's got an extra Z80 for controlling the YM2203 soundchip. It's common for arcade hardware to have a separate CPU dedicated to sound.

Other than you having fun hacking/converting the game, I don't think this game is worth it, it's a bad game, and not many people would want to "play them with inversion of the horizontal and vertical dimensions !" Tongue

By muffie

Paladin (933)

muffie's picture

20-01-2009, 18:58

How the second z80 is accessed?

I'm executing my code:
...
ld...
out...
in...
...

how can I know (control) what the other z80 is doing?

By hap

Paragon (2012)

hap's picture

20-01-2009, 19:08

use the MAME debugger Smile

By muffie

Paladin (933)

muffie's picture

20-01-2009, 19:23

Smile
But do you know the answer? A high level explanation would be nice...
Anyway, that should be difficult to adapt isnt it?

By hap

Paragon (2012)

hap's picture

20-01-2009, 20:02

I don't know, I haven't looked at how the game exactly works. Use MAME source + debugger to find out.

By Patsie

Master (248)

Patsie's picture

21-01-2009, 11:21

How the second z80 is accessed?

I'm executing my code:
...
ld...
out...
in...
...

how can I know (control) what the other z80 is doing?

You're thinking like one CPU is controling the other, but it's not. CPU1 is executing code from 1 piece of memory and CPU2 is executing code in an entirely different piece of memory (maybe even physically different memory) The CPU's can perhaps interact through an I/O bus or through some shared memory. So code that is running on the 'sound cpu' can say: "play music X until you get interrupt A and then play music Y" and the 'game cpu' handles the game and when it's game over, sends a new I/O, interrupt, shared mem change to the sound cpu.

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