Newbie Cheat Conversion XML to DAT

[editing101]

Hi guys,

I'm currently using MAME 073 in Retroarch on my Nintendo Switch for portable MAME emulation. MAME 0.73 is supposedly the only up to date core available. I've previously used more up to date versions of MAME on my Android, but Android requires the use of touch screen controls and my switch controllers are more intuitive and user friendly in using MAME.

As MAME 0.73 only supports the "cheat.dat" file, I've tried converting some of the "XML" cheats to use in this older version, but have had no success in getting them to work.

I'm a relative newbie to MAME cheat creation, but I am aware that in the old "cheat.dat" file:

The :39900000: prefix refers to ROM cheats that interact with the RAM addresses in the game code and can activate modes or functions withini the game. (These can be toggled ON or OFF on the MAME cheat menu).

The :00000000: prefix refers to RAM cheats that poke RAM directly and can change lives, health, ammo e.g. elements that changing constantly. (These can operate upon choosing the SET option on the MAME cheat menu).

With this in mind, I've tried converting some of the more recent cheats for NBA JAM into the old cheat.dat format and had no success. Here's a few examples:

Activate Shot % Display (Learning Mode 2)

Code: Select all

<action>maincpu.pw@10F1290=0001</action>

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:nbajam:39900000:0F1290:00000001:FFFFFFFF:Shot % Display (Learning Mode 2)

P1 Powerup Defense

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<action>maincpu.pw@10F1250=0008</action>

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:nbajam:39900000:0F1250:00000008:FFFFFFFF:Power Up Defense

P1 Big Head

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<action>maincpu.pw@1600000=8F8F</action>
<action>maincpu.pw@10E59C0=0001|(maincpu.pw@10E59C0 BAND ~0001)</action>

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:nbajam:39900000:600000:00008F8F:00008F8F:P1 Big Head
:nbajam:39900000:0E59C0:00000001:00000001:P1 Big Head (2/2)

Player 1 Always on Fire

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<action>maincpu.pw@10E9A=0000> 

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:nbajam:39900000:0E9A30:00000000:FFFFFFFF:P1 Always On Fire

Never Miss A Shot ON

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<action>maincpu.mw@000FE56=CB76</action>
<action>maincpu.mw@00102D6=C400</action>

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:nbajam:39900000:00FE56:0000CB76:FFFFFFFF:Never Miss A Shot ON
:nbajam:39900000:0102D6:0000C400:FFFFFFFF:Never Miss A Shot ON

Can anyone (hopefully Pugsy?) offer some advice on the correct method of converting these or refer me to a tool that can do so? (None of my 'converted' cheats seem to work at present! )

I would greatly appreciate anything anyone can tell me.

Thank you.

[Pugsy]

Basically you are trying to convert cheats for the latest MAME to work with a MAME version from 21 years ago!

Normal games are doable to a degree, BUT versions of roms change over the years as newer versions of the roms are dumped and become the new parent set.

With nbajam you also and the issue that the driver used to have a very different memory addressing system as well.

You've over simplified what ":39900000:" is - definition of how the old types worked is at the top of cheat.dat. There where no ROM cheats for nbajam at the time - and I don't have a version (and dont want one) from that era with a debugger to check.

I shall however give you one final tip for nbajam you will likely need to divide any new 'RAM cheat' address by 8.

[editing101]

I see, thanks for explaining then !

Yeah, I know it's an unusual request - Nintendo Switch owners are stuck using an ancient version of MAME that has limited romset support. The roms that do work however, work really well.

Thanks for that, I'm going to get to work on dividing the RAM cheats and experimenting accordingly. I'm assuming that many of the 'normal' games (romsets that haven't had many changes over the years) do not require such divisions.

Much appreciated Pugsy, and thanks again !