mailbox move generator

[maksimKorzh]

Hi guys

I've forked stockfish to build Chinese chess engine.
There are a couple of good examples like Fairy Stockfish and Chameleon (derived from sf7)
However perft is extremely slow, My javascript engine's perft is even a bit faster than Chameleon's
(I know it sounds weird but I can share a video demonstrating this for those interested)

So I've started thinking about making array based version of Stockfish to play Chinese chess.
I do have a working movegenerator in javascript and it's not a problem to port it to C or C++,
I could've port my entire engine and be happy with 5x faster one however my goal is to start a commmunity
project with a code base comfortable to work with hence I want to use Stockfish's code base.

Now the tech issues:

• overall arch feels very monolithic and it's hard to modify highly optimized code (this one is rhetoric)
• Position class interface has tons of methods to work with bitboards
• not clear how to debug the code (I'm experienced in C/JS/Python but new to C++)

Possible solutions I'm currently reviewing:

1. Write a custom move generator and try to connect SF's search
2. Write a custom position class with the same interface but relying on mailbox board representation
3. Modify current code base (I'm getting core dumed errors with this approach all the time...)

So my questions are:

1. Does search rely on bitboard related data fields/methods within Position class? Can this be disabled? (I mean things like pawn hash keys)
2. Is current move encoding crucial? It seems like a move is encoded as 16 bit integer, however this might not be enough assuming greater square indexes of Chinese chess board (10x9 board), at very least the number of bits reserved for fromSq and to Sq would get exhausted at very least.
3. Is it possible to use search() as a module? (I actually don't need anything else from SF apart search, well and UCI that would be turned into UCCI one day apparently)

Looking for kind advise)

P.S. In my dreams:
I write my own movegen and then connect SF's search

[maksimKorzh]

Tried many different approaches...
Almost gave up...
But then simply realized that I can alter the size of "Piece board[SQUARE_NB]", add squares, ranks, files, piece types fix tons of errors
and actually still have a working engine (by "working" I mean no segfaults when evrything apart what I cuurently debug is disabled)

Never worked with other code but my own before and need to say that working with SF's code base is really exciting.
I loved how the bitboard related code is orginized - it's even a bit oity now to disable and later remove it)))

Many thanks to SF dev's for a clean code that is pleasant to work with!