Enhacklopedia usually notes the various formatting used by cheat devices for a given consolehttp://bsfree.org/hack/hacking_psx.html
Might as well also link as it has a bit more infohttp://problemkaputt.de/psx-spx.htm#cheatdeviceshttps://gamehacking.org/faqs/hackv500c.html#learn_your_shark
Sometimes cheat device makers encrypted their devices (making cheats for everything is hard work https://www.eurogamer.net/articles/2016-09-24-game-genie-declassified-that-summer-i-played-230-game-boy-games
) so you can also have that to deal with. Anything like that has long since been broken but might be only as a standalone program rather than a conversion tool
Cheats tend to consist of three parts
1) What cheat format it is
2) Where the cheat needs to land
3) What to set the value to where it lands or thing to compare against.
Converting is usually then a matter of changing those into the format used by another. The main program, other than any potential encryption, is when different devices/formats have different abilities and you get to work around those.
Depending upon the device you may or may not need the activation codes/master codes for things either (emulators don't need an injection point as they are emulators and can write what they like, where they like, flash carts and mod chips can also be similarly untroubled or have their own databases) but that you get to approach on a system by system/case by case basis.
Not sure what that format is (read a review of it http://www.psillustrated.com/psillustrated/hard_rev.php/242/xploder-cd-9000-playstation.html
) and might be rather more custom than some of the stuff above details.
If it is just infinite health and mana for Diablo (don't know why you would be doing the PS1 version of the game, even more so since it helped give source code for it) and is that simple you can probably remake it -- fire up an emulator with cheat search, start the search, lose some health and search for something that changed, lose some health and search... numbers of possibilities will go down and down. At that point you then know the where and can force it normal. Do the same for mana.
In some cases the developers will do things to prevent cheats but that should be simple enough.
Or indeed someone made better ones (hopefully it is the same region/version as you).https://www.cheatcc.com/psx/codes/d.html
Those there are split into two cheats. Looks like the max health value is greater than a simple single cheat can reach they do two right next to each other (0001 FFFF = 131071, as opposed to FFFF which = 65535).