# <div align="center"> Laura-Core</div>
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[![Crates.io Version][crates-badge]][crates-link]
[![License][license-badge]][license-link]
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**Laura-Core** a fast and efficient move generator for chess engines.
## Features
- **Bitboards** for efficient board representation.
- **Zobrist Hashing**
- **Black Magic Bitboards** for rapid move generation of rooks, bishops, and queens.
- **PEXT Bitboards** as an alternative for efficient sliding piece move generation.
- **Supports full legal move generation or selective move filtering (quiet or tactical moves)**
- **FEN support**: Initialize the board from a FEN string.
- **Move execution** to update the board state dynamically.
- **Null move support** for search optimizations like null move pruning.
- **UCI move execution**: Apply moves directly from a UCI-compliant string.
- **Fully `#![no_std]` compatible**
## Compilation Recommendations
If your processor supports **BMI2** (e.g., **Intel Haswell** (2013+) or **AMD Zen 3** (Nov 2020+)), it is recommended to compile with `RUSTFLAGS="-C target-cpu=native"` and enable the `bmi2` feature for better performance.
**Laura-Core** provides a feature called **`bmi2`**, which enables the use of the **`pext`** instruction for more efficient bit manipulation.
For older processors **without** BMI2 support, only `RUSTFLAGS="-C target-cpu=native"` should be used, as the `bmi2` feature will not work on unsupported hardware.
## **Usage**
### **Setting up the initial board**
```rust
use laura_core::Board;
let board: Board = Board::default();
assert_eq!(board.to_fen(), "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
```
### **Initialize a board from a FEN string**
You can create a `Board` from a FEN (Forsyth-Edwards Notation) string using the `FromStr` trait:
```rust
use std::str::FromStr;
use laura_core::Board;
let fen: &str = "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1";
let board: Board = Board::from_str(fen).unwrap();
assert_eq!(board, Board::kiwipete());
```
### **Generate all legal moves**
To generate moves from a given position, use the gen_moves function along with one of the predefined constants:
- `ALL_MOVES`: Generates all legal moves.
- `QUIET_MOVES`: Generates only quiet moves (non-capturing moves).
- `TACTICAL_MOVES`: Generates tactical moves (captures and queen promotions).
**Example: Generating all legal moves**
This example starts from the default position and generate all legal moves.
```rust
use laura_core::{gen_moves, Board, MoveList, ALL_MOVES};
let board: Board = Board::default();
let moves: MoveList = gen_moves::<ALL_MOVES>(&board);
assert_eq!(moves.len(), 20);
```
**Example: Generating only quiet moves**
```rust
use laura_core::{gen_moves, Board, MoveList, QUIET_MOVES};
let board: Board = Board::kiwipete();
let moves: MoveList = gen_moves::<QUIET_MOVES>(&board);
assert_eq!(moves.len(), 40);
```
**Example: Generating only tactical moves**
```rust
use laura_core::{gen_moves, Board, MoveList, TACTICAL_MOVES};
let board: Board = Board::kiwipete();
let moves: MoveList = gen_moves::<TACTICAL_MOVES>(&board);
assert_eq!(moves.len(), 8);
```
### **Execute moves**
You can apply a move to the board using UCI (Universal Chess Interface) notation:
```rust
use laura_core::Board;
let board: Board = Board::default();
let new: Board = board.make_uci_move("e2e4").unwrap();
assert_eq!(new.to_fen(), "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1");
```
This executes the move e2e4 (pawn to e4) and asserts the updated board position.
## Benchmarks
**Test system:** AMD Ryzen 5 5600G (3.9 GHz), 32 GB DDR4 3200 MHz, Windows 10
|**Start Position (6)**|410 MN/s|625 MN/s|434 MN/s|640 MN/s|
| **Kiwipete (5)**|531 MN/s|840 MN/s|564 MN/s|910 MN/s|
**\*** Compiled with `RUSTFLAGS="-C target-cpu=native"` for hardware-specific optimization.
## Changelog
All notable changes are documented in the [CHANGELOG][changelog-link].
For details on the latest updates, bug fixes, and improvements, check the full changelog.
## **License**
This project is licensed under **GPLv3**. See the [LICENSE][license-link] file for details.
[changelog-link]:https://github.com/hanstibberio/Laura/blob/master/laura_core/CHANGELOG.md
[license-link]:https://github.com/hanstibberio/Laura/blob/master/LICENSE
[license-badge]:https://img.shields.io/github/license/hanstibberio/laura?label=license&color=success
[crates-link]:https://crates.io/crates/laura_core
[crates-badge]:https://img.shields.io/crates/v/laura_core