cubequest infinite boss time (for pugsy)

[asper]

Hi pugsy,

I tryed to find that cheat for cubequest using artmoney pro (just like firefox) but I have a problem: I correctly found credits and counter locations with artmoney pro but it seems to be impossible to find the correspective memory location in the mame debugger for both of them... maybe the location i not inmemory but is something rom-related ?

The credits follow a simple counter while the time that appears when you reach the cube (21 "seconds") use a VERY STRANGE decremental function (I found the location after finding the credits location and limiting the search in artmoney pro within: credit location+FFFFFF and using "new value is decreased" each time the counter decrement by 1).

Can you help me explaining how to find this value in mame debugger ??? (deadbeef won't work this time... )

[Pugsy]

Can you help me explaining how to find this value in mame debugger ??? (deadbeef won't work this time... )

deadbeef is just a collection of memorable characters...it will work for lots of things but the endianness of the MAME driver and whether it starts on a odd or even address can cause it to appear as different things in the mame debugger like ADDEEFBE.

Rather than explain endiananess and give us both a headache, just find a series of consecutive identical bytes which are not used elsewhere.

So in the MAME debugger do a series of finds to you get a result with no returns or very few returns

eg
F 0,ffffff,w.0000 will have lots of returns
F 0,ffffff,w.bebe should have none or very few
so instead of poking deadbeef poke bebebebe
and then F 0,ffffff,w.bebe should return the rough area of the address you are interested in (the extra addresses not returned in the original find)

[Mohsin]

10.99 GB for a 1983 game, no wonder nobody posted its cheats yet.

[Pugsy]

10.99 GB for a 1983 game, no wonder nobody posted its cheats yet.

Aye, if only there was a way of these laserdisc games to have a lower res and hence smaller chds..

cubeqst does seem to work without the chd (you have to wait for the countdowns to finish though), obviously backdrops are missing but gameplay seems pretty much intact.


EDIT: I've added a ROM Invincibility cheat for this game here :- viewtopic.php?f=4&t=3273

[Mohsin]

wow it does really works, but the countdown is a bit longer than i expected, its just a 38 min video backdrop on a 10.99GB disk

[asper]

Thank you pugsy for the invincibility cheat !!!
Th3 video is so short and big because it is the bit-per-bit copy of the original LD game; mame want to preserve ORIGINAL features, anyway the game works even without it.

I need to find this counter cheat, I hope to find it (the game ends and show you ending sequence, when you kill the last very-colored cube in the opposite vertex of the cube, then it starts again from the beginning) and the time is really too little to destroy it so I am trying to find that cheat.

I will try to find that address but still not able to do it... how big is the 68000 memory ? FFFFFF ?

Anyway I think it will show the end even with rom cheat ! So maybe stopping the counter won't be so useful

Thanks again pugsy !!!

If you can try to explain me how to make a rom cheat... I mean what routines have I to search inside the debugger... like a mini-guide... I am thirsty of knowledge

[Mohsin]

If you can try to explain me how to make a rom cheat... I mean what routines have I to search inside the debugger... like a mini-guide... I am thirsty of knowledge

i guess it will require learning assembly. also guess it will not be mini.

[Pugsy]

I will try to find that address but still not able to do it... how big is the 68000 memory ? FFFFFF ?

Yes the 68000 has a 24bit address bus, so address range is 0 to FFFFFF.. However for cubequest it'ss highly llikely that the RAM is only upto 0x40000 and the rest is unused as RAM or not fitted.

Anyway I think it will show the end even with rom cheat ! So maybe stopping the counter won't be so useful

Using bebebebe and searching for bebe should work though...

If you can try to explain me how to make a rom cheat... I mean what routines have I to search inside the debugger... like a mini-guide... I am thirsty of knowledge

It would be a massive topic....learning the basics of assembly would be a pre-requisite and I could help out on a one-to-one basis for individual cheats, guide is a non-starter.

[Mohsin]

a place to start would be

http://webster.cs.ucr.edu/

they have put a very good free book, although it will still require some basic knowledge of functions and operators.

[asper]

Thank you all men !

[asper]

It seems to work now:

<cheat desc="Unlimited Boss Time">
<script state="run">
<action>main_cpu.pb@03FBF8=12</action>
<action>main_cpu.pb@03FBF9=51</action>
<action>main_cpu.pb@03FBFA=00</action>
<action>main_cpu.pb@03FBFB=12</action>
</script>
</cheat>

The problem was that bytes were inverted (2by2) in 68000 memory and in artmoney pro memory... is this the little/big endian ? Is there a way to revert it in mame debugger ?

I don't know if it will work as infinite time but I tested it for 5 mins and works... but I feel that the counter is still running... anyway now it is usable !

[Pugsy]

The problem was that bytes were inverted (2by2) in 68000 memory and in artmoney pro memory... is this the little/big endian ? Is there a way to revert it in mame debugger ?

Yes it's an endian issue, possibly linked to odd/even address mismatches between the debugger and the external cheat program.

Intel 80386 and compats are Little Endian, along with z80 & 6502 + others

680x & 680xx + others are Big Endian

AFAIK (never looked into it) there's no way to 'revert' it in the MAME debugger....it's the way it is. It's one of the reasons why external cheat programs are such a pain to use with MAME, having to consider endianness when finding cheats is just one more frustration.


BTW, you could probably to a double word write instead of 4 single byte writes:

Code: Select all

main_cpu.pd@03FBF8=12510012

Update:

I've just looked at the code if you do a 'wp 3fbf8,1,w' you will see it only changes a word (2 bytes), and the maximum value that is displayed correctly is 32...so the write should look like this:-

Code: Select all

main_cpu.pw@03FBF8=03c0

3co represents 32 seconds
so I'm surmising here that it will be decrementing every frame...say there's 30 frames per second, so you have a total of 32 * 30 frames = 960 frames (960 in decimal = 3c0 in hex)

[asper]

WOW ! How do you find out that time is frame-dependant ???

(thank you for the other debugging tricks !)

[stephh]

WOW ! How do you find out that time is frame-dependant ???

It's a known issue that happens in many games ... To check this, pause the game, initialise search, go to next frame (Shift + P), search for values decremented by one, repeat until you find only one value ... Note that such "trick" is also very useful for games with invulnerability timers ...

Steph from The Ultimate Patchers