Squares as index

Cargo.toml

@@ -2,6 +2,7 @@
 name = "Mouse"
 version = "0.1.0"
 edition = "2024"
+build = "build/build.rs"
 
 [lib]
 name = "mouse"
@@ -14,7 +15,7 @@ codegen-units = 1
 lto = true
 
 [dev-dependencies]
-criterion = "0.7.0"
+criterion = "0.8.2"
 iai = { git = "https://github.com/sigaloid/iai", rev = "d56a597" }
 perft_fixtures = { path = "perft_fixtures" }
 

build/build.rs

@@ -0,0 +1,99 @@
+use std::fs;
+
+mod gen_caches_non_sliders;
+mod gen_caches_sliders;
+mod gen_util;
+
+const DIR_PATH: &str = "src/backend/";
+
+fn main() {
+    println!("cargo:rerun-if-changed=build/build.rs");
+    println!("cargo:rerun-if-changed=build/gen_caches_non_sliders.rs");
+    println!("cargo:rerun-if-changed=build/gen_caches_sliders.rs");
+    println!("cargo:rerun-if-changed=build/gen_util.rs");
+    println!("cargo:rerun-if-changed=src/backend/caches.rs");
+
+    let mut king_moves = [0u64; 64];
+    for (square, king_moves_for_square) in king_moves.iter_mut().enumerate() {
+        *king_moves_for_square = gen_caches_non_sliders::gen_king_moves(square as i8);
+    }
+
+    let mut knight_moves = [0u64; 64];
+    for (square , knight_moves_for_square) in knight_moves.iter_mut().enumerate() {
+        *knight_moves_for_square = gen_caches_non_sliders::gen_knight_moves(square as i8);
+    }
+
+    let capture_pawn_moves = gen_caches_non_sliders::gen_pawn_captures();
+
+    let pext_data = gen_caches_sliders::gen_cache_sliders();
+    let rook_pext_mask = pext_data.rook_pext_mask;
+    let rook_pext_index = pext_data.rook_pext_index;
+    let bishop_pext_mask = pext_data.bishop_pext_mask;
+    let bishop_pext_index = pext_data.bishop_pext_index;
+    let pext_table = pext_data.pext_table;
+
+    let cache_strings = [
+        format!(
+            "pub const KING_MOVES: [BitBoard; SQUARES_AMOUNT] = unsafe{{std::mem::transmute({})}};",
+            array_to_string(&king_moves)
+        ),
+        format!(
+            "pub const KNIGHT_MOVES: [BitBoard; SQUARES_AMOUNT] = unsafe{{std::mem::transmute({})}};",
+            array_to_string(&knight_moves)
+        ),
+        format!(
+            "pub const PAWN_CAPTURE_MOVES: [[BitBoard; SQUARES_AMOUNT]; SIDES] = unsafe{{std::mem::transmute([{}, {}])}};",
+            array_to_string(&capture_pawn_moves[0]),
+            array_to_string(&capture_pawn_moves[1])
+        ),
+        format!(
+            "pub const ROOK_PEXT_MASK: [BitBoard; SQUARES_AMOUNT] = unsafe{{std::mem::transmute({})}};",
+            array_to_string(&rook_pext_mask)
+        ),
+        format!(
+            "pub const ROOK_PEXT_INDEX: [usize; SQUARES_AMOUNT] = {:?};",
+            rook_pext_index
+        ),
+        format!(
+            "pub const BISHOP_PEXT_MASK: [BitBoard; SQUARES_AMOUNT] = unsafe{{std::mem::transmute({})}};",
+            array_to_string(&bishop_pext_mask)
+        ),
+        format!(
+            "pub const BISHOP_PEXT_INDEX: [usize; SQUARES_AMOUNT] = {:?};",
+            bishop_pext_index
+        ),
+        format!(
+            "pub static PEXT_TABLE: [BitBoard; {}] = unsafe{{std::mem::transmute({})}};",
+            gen_caches_sliders::PEXT_TABLE_SIZE,
+            array_to_string(&pext_table)
+        ),
+    ];
+
+    let mut file_content = String::from(
+        "// DO NOT EDIT THIS FILE.
+// IT WAS AUTOGENERATED BY THE BUILD SCRIPT!
+
+use crate::backend::state::board::bitboard::BitBoard;
+use crate::backend::constants::SQUARES_AMOUNT;
+use crate::backend::constants::SIDES;
+",
+    );
+    for string in cache_strings {
+        file_content.push_str("#[rustfmt::skip]\n");
+        file_content.push_str(&string);
+        file_content.push_str("\n\n");
+    }
+
+    let full_path = format!("{}caches.rs", DIR_PATH);
+    fs::write(&full_path, file_content).unwrap();
+}
+
+fn array_to_string<const N: usize>(array: &[u64; N]) -> String {
+    let mut string = String::new();
+    string.push('[');
+    for bb in array {
+        string.push_str(&format!("{}u64,", bb));
+    }
+    string.push(']');
+    string
+}

build/gen_caches_non_sliders.rs

@@ -0,0 +1,111 @@
+use crate::gen_util::{
+    is_square_at_bottom_edge, is_square_at_left_edge, is_square_at_right_edge,
+    is_square_at_top_edge, is_square_valid, square_from_rank_and_file, square_to_bb,
+    square_to_file, square_to_rank,
+};
+
+/// Generates a `BitBoard` with all possible moves for a king piece from a given `Square`.
+pub fn gen_king_moves(square: i8) -> u64 {
+    let mut bitboard = 0;
+
+    let rank = square_to_rank(square);
+    let file = square_to_file(square);
+
+    for file_offset in -1..=1 {
+        for rank_offset in -1..=1 {
+            // skip the current square
+            if file_offset == 0 && rank_offset == 0 {
+                continue;
+            }
+            // create the relevant square
+            let current_rank = rank + rank_offset;
+            let current_file = file + file_offset;
+
+            // and add it if it's valid
+            if is_square_valid(current_rank, current_file) {
+                let current_square = current_rank * 8 + current_file;
+                let bb = square_to_bb(current_square);
+                bitboard |= bb;
+            }
+        }
+    }
+    bitboard
+}
+
+/// Same as above but for the knight.
+pub fn gen_knight_moves(square: i8) -> u64 {
+    let mut bitboard = 0;
+
+    let rank = square_to_rank(square);
+    let file = square_to_file(square);
+
+    // The offsets for the knight moves. Starting in the top left corner.
+    // `_ _ _ _ _ _ _ _`
+    // `_ _ 2 _ 3 _ _ _`
+    // `_ 1 _ _ _ 4 _ _`
+    // `_ _ _ K _ _ _ _`
+    // `_ 8 _ _ _ 5 _ _`
+    // `_ _ 7 _ 6 _ _ _`
+    // `_ _ _ _ _ _ _ _`
+    // `_ _ _ _ _ _ _ _`
+    let file_offset = [-2, -1, 1, 2, 2, 1, -1, -2];
+    let rank_offset = [1, 2, 2, 1, -1, -2, -2, -1];
+
+    for index in 0..8 {
+        // Calculate the current square.
+        let current_file = file + file_offset[index];
+        let current_rank = rank + rank_offset[index];
+
+        // If it is valid, add it to the bitboard.
+        if is_square_valid(current_rank, current_file) {
+            let current_square = square_from_rank_and_file(current_rank, current_file);
+            let bb = square_to_bb(current_square);
+            bitboard |= bb;
+        }
+    }
+
+    bitboard
+}
+
+pub fn gen_pawn_captures() -> [[u64; 64]; 2] {
+    let mut quiet_moves = [[0; 64]; 2];
+
+    for (side, quiet_moves_per_side) in quiet_moves.iter_mut().enumerate() {
+        // iterate over all squares
+        for square in 0..64 {
+            // and generate the moves for that square
+            quiet_moves_per_side[square as usize] = gen_pawn_captures_at_square(square, side == 0);
+        }
+    }
+
+    quiet_moves
+}
+
+fn gen_pawn_captures_at_square(square: i8, is_white: bool) -> u64 {
+    let mut bitboard: u64 = 0;
+    let mut current_square = square;
+
+    match is_white {
+        true => {
+            if is_square_at_top_edge(current_square) {
+                return bitboard;
+            }
+            current_square += 8;
+        }
+        false => {
+            if is_square_at_bottom_edge(current_square) {
+                return bitboard;
+            }
+            current_square -= 8;
+        }
+    }
+
+    if !is_square_at_right_edge(current_square) {
+        bitboard |= square_to_bb(current_square + 1);
+    }
+    if !is_square_at_left_edge(current_square) {
+        bitboard |= square_to_bb(current_square - 1);
+    }
+
+    bitboard
+}