use std::mem;
use crate::{Bitboard, Color, FILE_COUNT, PIECE_TYPE_COUNT, SQUARE_COUNT, File, Piece, Position, Score, Square};
#[allow(unused_imports)]
use crate::MoveMasks;
const BASE_PIECE_SCORES: [i16; PIECE_TYPE_COUNT] = [100, 300, 320, 500, 900, 10000, 100, 300, 320, 500, 900, 10000];
const OPENING_PIECE_SCORES: [i16; PIECE_TYPE_COUNT] = [82, 337, 365, 477, 1025, 12000, 82, 337, 365, 477, 1025, 12000];
const ENDGAME_PIECE_SCORES: [i16; PIECE_TYPE_COUNT] = [94, 281, 297, 512, 936, 12000, 94, 281, 297, 512, 936, 12000];
const BASE_PAWN_POSITION_SCORES: [i16; SQUARE_COUNT] = [
90, 90, 90, 90, 90, 90, 90, 90,
30, 30, 30, 40, 40, 30, 30, 30,
20, 20, 25, 30, 30, 25, 20, 20,
10, 10, 10, 20, 20, 10, 10, 10,
5, 5, 10, 20, 20, 5, 5, 5,
0, 0, 0, 5, 5, -5, 0, 0,
0, 0, 0, -10, -10, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
];
const BASE_KNIGHT_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-15, -5, 0, 0, 0, 0, -5, -15,
-5, 0, 0, 10, 10, 0, 0, -5,
-5, 5, 20, 20, 20, 20, 5, -5,
-5, 10, 20, 30, 30, 20, 10, -5,
-5, 10, 20, 30, 30, 20, 10, -5,
-5, 5, 20, 10, 10, 20, 5, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-10, -10, 0, 0, 0, 0, -10, -10,
];
const BASE_BISHOP_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-5, 0, 0, 0, 0, 0, 0, -5,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 5, 5, 0, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
0, 10, 0, 5, 5, 0, 10, 0,
0, 30, 0, 0, 0, 0, 30, 0,
0, 0, -10, 0, 0, -10, 0, 0,
];
const BASE_ROOK_POSITION_SCORES: [i16; SQUARE_COUNT] = [
50, 50, 50, 50, 50, 50, 50, 50,
50, 50, 50, 50, 50, 50, 50, 50,
0, 0, 10, 20, 20, 10, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
0, 0, 10, 20, 20, 10, 0, 0,
];
const BASE_QUEEN_POSITION_SCORES: [i16; SQUARE_COUNT] = [
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
];
const BASE_KING_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-5, 0, 0, 0, 0, 0, 0, -5,
0, 0, 5, 5, 5, 5, 0, 0,
0, 5, 5, 10, 10, 5, 5, 0,
0, 5, 10, 20, 20, 10, 5, 0,
0, 5, 10, 20, 20, 10, 5, 0,
0, 0, 5, 10, 10, 5, 0, 0,
0, 5, 5, -5, -5, -5, 5, 0,
0, 5, 5, -5, -15, -5, 10, 0,
];
const BASE_PIECE_POSITION_SCORES: [&[i16; SQUARE_COUNT]; PIECE_TYPE_COUNT] = [
&BASE_PAWN_POSITION_SCORES, &BASE_KNIGHT_POSITION_SCORES, &BASE_BISHOP_POSITION_SCORES, &BASE_ROOK_POSITION_SCORES, &BASE_QUEEN_POSITION_SCORES, &BASE_KING_POSITION_SCORES,
&BASE_PAWN_POSITION_SCORES, &BASE_KNIGHT_POSITION_SCORES, &BASE_BISHOP_POSITION_SCORES, &BASE_ROOK_POSITION_SCORES, &BASE_QUEEN_POSITION_SCORES, &BASE_KING_POSITION_SCORES,
];
const OPENING_PAWN_POSITION_SCORES: [i16; SQUARE_COUNT] = [
0, 0, 0, 0, 0, 0, 0, 0,
98, 134, 61, 95, 68, 126, 34, -11,
-6, 7, 26, 31, 65, 56, 25, -20,
-14, 13, 6, 21, 23, 12, 17, -23,
-27, -2, -5, 12, 17, 6, 10, -25,
-26, -4, -4, -10, 3, 3, 33, -12,
-35, -1, -20, -23, -15, 24, 38, -22,
0, 0, 0, 0, 0, 0, 0, 0,
];
const OPENING_KNIGHT_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-167, -89, -34, -49, 61, -97, -15, -107,
-73, -41, 72, 36, 23, 62, 7, -17,
-47, 60, 37, 65, 84, 129, 73, 44,
-9, 17, 19, 53, 37, 69, 18, 22,
-13, 4, 16, 13, 28, 19, 21, -8,
-23, -9, 12, 10, 19, 17, 25, -16,
-29, -53, -12, -3, -1, 18, -14, -19,
-105, -21, -58, -33, -17, -28, -19, -23,
];
const OPENING_BISHOP_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-29, 4, -82, -37, -25, -42, 7, -8,
-26, 16, -18, -13, 30, 59, 18, -47,
-16, 37, 43, 40, 35, 50, 37, -2,
-4, 5, 19, 50, 37, 37, 7, -2,
-6, 13, 13, 26, 34, 12, 10, 4,
0, 15, 15, 15, 14, 27, 18, 10,
4, 15, 16, 0, 7, 21, 33, 1,
-33, -3, -14, -21, -13, -12, -39, -21,
];
const OPENING_ROOK_POSITION_SCORES: [i16; SQUARE_COUNT] = [
32, 42, 32, 51, 63, 9, 31, 43,
27, 32, 58, 62, 80, 67, 26, 44,
-5, 19, 26, 36, 17, 45, 61, 16,
-24, -11, 7, 26, 24, 35, -8, -20,
-36, -26, -12, -1, 9, -7, 6, -23,
-45, -25, -16, -17, 3, 0, -5, -33,
-44, -16, -20, -9, -1, 11, -6, -71,
-19, -13, 1, 17, 16, 7, -37, -26,
];
const OPENING_QUEEN_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-28, 0, 29, 12, 59, 44, 43, 45,
-24, -39, -5, 1, -16, 57, 28, 54,
-13, -17, 7, 8, 29, 56, 47, 57,
-27, -27, -16, -16, -1, 17, -2, 1,
-9, -26, -9, -10, -2, -4, 3, -3,
-14, 2, -11, -2, -5, 2, 14, 5,
-35, -8, 11, 2, 8, 15, -3, 1,
-1, -18, -9, 10, -15, -25, -31, -50,
];
const OPENING_KING_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-65, 23, 16, -15, -56, -34, 2, 13,
29, -1, -20, -7, -8, -4, -38, -29,
-9, 24, 2, -16, -20, 6, 22, -22,
-17, -20, -12, -27, -30, -25, -14, -36,
-49, -1, -27, -39, -46, -44, -33, -51,
-14, -14, -22, -46, -44, -30, -15, -27,
1, 7, -8, -64, -43, -16, 9, 8,
-15, 36, 12, -54, 8, -28, 24, 14,
];
const OPENING_PIECE_POSITION_SCORES: [&[i16; SQUARE_COUNT]; PIECE_TYPE_COUNT] = [
&OPENING_PAWN_POSITION_SCORES, &OPENING_KNIGHT_POSITION_SCORES, &OPENING_BISHOP_POSITION_SCORES, &OPENING_ROOK_POSITION_SCORES, &OPENING_QUEEN_POSITION_SCORES, &OPENING_KING_POSITION_SCORES,
&OPENING_PAWN_POSITION_SCORES, &OPENING_KNIGHT_POSITION_SCORES, &OPENING_BISHOP_POSITION_SCORES, &OPENING_ROOK_POSITION_SCORES, &OPENING_QUEEN_POSITION_SCORES, &OPENING_KING_POSITION_SCORES,
];
const ENDGAME_PAWN_POSITION_SCORES: [i16; SQUARE_COUNT] = [
0, 0, 0, 0, 0, 0, 0, 0,
178, 173, 158, 134, 147, 132, 165, 187,
94, 100, 85, 67, 56, 53, 82, 84,
32, 24, 13, 5, -2, 4, 17, 17,
13, 9, -3, -7, -7, -8, 3, -1,
4, 7, -6, 1, 0, -5, -1, -8,
13, 8, 8, 10, 13, 0, 2, -7,
0, 0, 0, 0, 0, 0, 0, 0,
];
const ENDGAME_KNIGHT_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-58, -38, -13, -28, -31, -27, -63, -99,
-25, -8, -25, -2, -9, -25, -24, -52,
-24, -20, 10, 9, -1, -9, -19, -41,
-17, 3, 22, 22, 22, 11, 8, -18,
-18, -6, 16, 25, 16, 17, 4, -18,
-23, -3, -1, 15, 10, -3, -20, -22,
-42, -20, -10, -5, -2, -20, -23, -44,
-29, -51, -23, -15, -22, -18, -50, -64,
];
const ENDGAME_BISHOP_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-14, -21, -11, -8, -7, -9, -17, -24,
-8, -4, 7, -12, -3, -13, -4, -14,
2, -8, 0, -1, -2, 6, 0, 4,
-3, 9, 12, 9, 14, 10, 3, 2,
-6, 3, 13, 19, 7, 10, -3, -9,
-12, -3, 8, 10, 13, 3, -7, -15,
-14, -18, -7, -1, 4, -9, -15, -27,
-23, -9, -23, -5, -9, -16, -5, -17,
];
const ENDGAME_ROOK_POSITION_SCORES: [i16; SQUARE_COUNT] = [
13, 10, 18, 15, 12, 12, 8, 5,
11, 13, 13, 11, -3, 3, 8, 3,
7, 7, 7, 5, 4, -3, -5, -3,
4, 3, 13, 1, 2, 1, -1, 2,
3, 5, 8, 4, -5, -6, -8, -11,
-4, 0, -5, -1, -7, -12, -8, -16,
-6, -6, 0, 2, -9, -9, -11, -3,
-9, 2, 3, -1, -5, -13, 4, -20,
];
const ENDGAME_QUEEN_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-9, 22, 22, 27, 27, 19, 10, 20,
-17, 20, 32, 41, 58, 25, 30, 0,
-20, 6, 9, 49, 47, 35, 19, 9,
3, 22, 24, 45, 57, 40, 57, 36,
-18, 28, 19, 47, 31, 34, 39, 23,
-16, -27, 15, 6, 9, 17, 10, 5,
-22, -23, -30, -16, -16, -23, -36, -32,
-33, -28, -22, -43, -5, -32, -20, -41,
];
const ENDGAME_KING_POSITION_SCORES: [i16; SQUARE_COUNT] = [
-74, -35, -18, -18, -11, 15, 4, -17,
-12, 17, 14, 17, 17, 38, 23, 11,
10, 17, 23, 15, 20, 45, 44, 13,
-8, 22, 24, 27, 26, 33, 26, 3,
-18, -4, 21, 24, 27, 23, 9, -11,
-19, -3, 11, 21, 23, 16, 7, -9,
-27, -11, 4, 13, 14, 4, -5, -17,
-53, -34, -21, -11, -28, -14, -24, -43
];
const ENDGAME_PIECE_POSITION_SCORES: [&[i16; SQUARE_COUNT]; PIECE_TYPE_COUNT] = [
&ENDGAME_PAWN_POSITION_SCORES, &ENDGAME_KNIGHT_POSITION_SCORES, &ENDGAME_BISHOP_POSITION_SCORES, &ENDGAME_ROOK_POSITION_SCORES, &ENDGAME_QUEEN_POSITION_SCORES, &ENDGAME_KING_POSITION_SCORES,
&ENDGAME_PAWN_POSITION_SCORES, &ENDGAME_KNIGHT_POSITION_SCORES, &ENDGAME_BISHOP_POSITION_SCORES, &ENDGAME_ROOK_POSITION_SCORES, &ENDGAME_QUEEN_POSITION_SCORES, &ENDGAME_KING_POSITION_SCORES,
];
const OPENING_PHASE_CUTOFF: i16 = 6192;
const ENDGAME_PHASE_CUTOFF: i16 = 518;
const FLIPPED_SQUARE_INDEX: [usize; SQUARE_COUNT] = [
56, 57, 58, 59, 60, 61, 62, 63,
48, 49, 50, 51, 52, 53, 54, 55,
40, 41, 42, 43, 44, 45, 46, 47,
32, 33, 34, 35, 36, 37, 38, 39,
24, 25, 26, 27, 28, 29, 30, 31,
16, 17, 18, 19, 20, 21, 22, 23,
8, 9, 10, 11, 12, 13, 14, 15,
0, 1, 2, 3, 4, 5, 6, 7,
];
const DOUBLED_PAWN_SCORE: i16 = -30;
const ISOLATED_PAWN_SCORE: i16 = -15;
const PASSED_PAWN_SCORES: [i16; FILE_COUNT] = [0, 10, 30, 50, 75, 100, 150, 200];
const SEMI_OPEN_FILE_SCORE: i16 = 10;
const OPEN_FILE_SCORE: i16 = 15;
const KING_ON_SEMI_OPEN_FILE_SCORE: i16 = -30;
const KING_ADJACENCY_SCORE: i16 = 15;
const PSEUDO_PIN_SCORE: i16 = 20;
const BISHOP_PAIR_SCORE: i16 = 20;
const CHECK_SCORE: i16 = 30;
const ATTACK_UNITS_SCORE: i16 = 10;
static mut FILE_MASKS: [Bitboard; SQUARE_COUNT] = unsafe { mem::zeroed() };
static mut RANK_MASKS: [Bitboard; SQUARE_COUNT] = unsafe { mem::zeroed() };
static mut ISOLATED_MASKS: [Bitboard; SQUARE_COUNT] = unsafe { mem::zeroed() };
static mut WHITE_PASSED_MASKS: [Bitboard; SQUARE_COUNT] = unsafe { mem::zeroed() };
static mut BLACK_PASSED_MASKS: [Bitboard; SQUARE_COUNT] = unsafe { mem::zeroed() };
#[derive(Clone, Copy, Debug)]
enum GamePhase {
Opening,
Middlegame,
Endgame,
}
pub struct EvalPosition;
impl EvalPosition {
pub(crate) unsafe fn init_positional_masks() {
Self::init_file_masks();
Self::init_rank_masks();
Self::init_isolated_masks();
Self::init_passed_masks();
}
unsafe fn init_file_masks() {
for square in Square::ALL_SQUARES {
FILE_MASKS[square] = Bitboard::ALL_FILES[square.file() as usize];
}
}
unsafe fn init_rank_masks() {
for square in Square::ALL_SQUARES {
RANK_MASKS[square] = Bitboard::ALL_RANKS[square.rank() as usize];
}
}
unsafe fn init_isolated_masks() {
for square in Square::ALL_SQUARES {
if square.file() != File::FA {
ISOLATED_MASKS[square] |= Bitboard::ALL_FILES[square.file() as usize - 1];
}
if square.file() != File::FH {
ISOLATED_MASKS[square] |= Bitboard::ALL_FILES[square.file() as usize + 1];
}
}
}
unsafe fn init_passed_masks() {
for square in Square::ALL_SQUARES {
for color in [Color::White, Color::Black] {
#[allow(static_mut_refs)]
let passed_masks_ref = match color {
Color::White => &mut WHITE_PASSED_MASKS,
Color::Black => &mut BLACK_PASSED_MASKS,
};
(*passed_masks_ref)[square] |= Bitboard::ALL_FILES[square.file() as usize];
if square.file() != File::FA {
(*passed_masks_ref)[square] |= Bitboard::ALL_FILES[square.file() as usize - 1];
}
if square.file() != File::FH {
(*passed_masks_ref)[square] |= Bitboard::ALL_FILES[square.file() as usize + 1];
}
match color {
Color::White => {
for &rank_bb in Bitboard::ALL_RANKS[square.rank() as usize..].iter() {
(*passed_masks_ref)[square] &= !rank_bb;
}
},
Color::Black => {
for &rank_bb in Bitboard::ALL_RANKS[..=square.rank() as usize].iter() {
(*passed_masks_ref)[square] &= !rank_bb;
}
},
}
}
}
}
#[inline(always)]
pub(crate) fn get_base_piece_position_score(piece: Piece, square: Square, color: Color) -> i16 {
BASE_PIECE_POSITION_SCORES[piece][Self::get_positional_index(square, color)]
}
#[inline(always)]
fn get_file_mask(square: Square) -> Bitboard {
unsafe { FILE_MASKS[square] }
}
#[inline(always)]
fn get_isolated_mask(square: Square) -> Bitboard {
unsafe { ISOLATED_MASKS[square] }
}
#[inline(always)]
fn get_white_passed_mask(square: Square) -> Bitboard {
unsafe { WHITE_PASSED_MASKS[square] }
}
#[inline(always)]
fn get_black_passed_mask(square: Square) -> Bitboard {
unsafe { BLACK_PASSED_MASKS[square] }
}
#[inline(always)]
pub(crate) fn get_game_phase_score(position: &Position) -> i16 {
let mut game_phase_score = 0;
for piece in Piece::ALL_PIECES_EXPECT_PAWNS_AND_KINGS {
game_phase_score += position.bitboards[piece].count_bits() as i16 * OPENING_PIECE_SCORES[piece];
}
game_phase_score
}
#[inline(always)]
pub(crate) fn get_game_phase_piece_score(piece: Piece) -> i16 {
OPENING_PIECE_SCORES[piece]
}
#[inline(always)]
fn get_game_phase(game_phase_score: i16) -> GamePhase {
if game_phase_score > OPENING_PHASE_CUTOFF {
GamePhase::Opening
} else if game_phase_score < ENDGAME_PHASE_CUTOFF {
GamePhase::Endgame
} else {
GamePhase::Middlegame
}
}
#[inline(always)]
fn get_positional_index(square: Square, color: Color) -> usize {
match color {
Color::White => square as usize,
Color::Black => FLIPPED_SQUARE_INDEX[square as usize],
}
}
#[inline(always)]
fn get_tapered_score(game_phase: GamePhase, game_phase_score: i16, opening_score: i16, endgame_score: i16) -> i16 {
match game_phase {
GamePhase::Middlegame => ((
opening_score as i32 * game_phase_score as i32 +
endgame_score as i32 * (OPENING_PHASE_CUTOFF as i32 - game_phase_score as i32)
) / OPENING_PHASE_CUTOFF as i32) as i16,
GamePhase::Opening => opening_score,
GamePhase::Endgame => endgame_score,
}
}
#[inline(always)]
pub fn eval(position: &Position) -> Score {
let mut score = Score::ZERO;
let mut opening_score = 0;
let mut endgame_score = 0;
let mut ao_copy = position.all_occupancy;
#[cfg(feature = "tapered_eval")]
let game_phase = Self::get_game_phase(position.game_phase_score);
while ao_copy != Bitboard::EMPTY {
let sq = ao_copy.pop_lsb();
let piece = position.get_piece(sq);
let piece_color_modifier = match piece.color() {
Color::White => 1,
Color::Black => -1,
};
let positional_index = Self::get_positional_index(sq, piece.color());
#[allow(unused_mut)]
let mut piece_score = 0;
#[cfg(not(feature = "tapered_eval"))]
{
piece_score += BASE_PIECE_SCORES[piece];
#[cfg(feature = "pst")]
{ piece_score += BASE_PIECE_POSITION_SCORES[piece][positional_index]; }
}
#[cfg(feature = "tapered_eval")]
{
opening_score += OPENING_PIECE_SCORES[piece] * piece_color_modifier;
endgame_score += ENDGAME_PIECE_SCORES[piece] * piece_color_modifier;
#[cfg(feature = "pst")]
{
opening_score += OPENING_PIECE_POSITION_SCORES[piece][positional_index] * piece_color_modifier;
endgame_score += ENDGAME_PIECE_POSITION_SCORES[piece][positional_index] * piece_color_modifier;
}
}
#[cfg(feature = "positional_eval")]
if piece == Piece::WP || piece == Piece::BP {
if (position.bitboards[piece] & Self::get_file_mask(sq)).count_bits() > 1 {
piece_score += DOUBLED_PAWN_SCORE;
}
if (position.bitboards[piece] & Self::get_isolated_mask(sq)).is_empty() {
piece_score += ISOLATED_PAWN_SCORE;
}
if piece == Piece::WP {
if (position.bitboards[Piece::BP] & Self::get_white_passed_mask(sq)).is_empty() {
piece_score += PASSED_PAWN_SCORES[7 - sq.rank() as usize];
}
} else {
if (position.bitboards[Piece::WP] & Self::get_black_passed_mask(sq)).is_empty() {
piece_score += PASSED_PAWN_SCORES[sq.rank() as usize];
}
}
} else if piece == Piece::WR || piece == Piece::BR {
if piece == Piece::WR {
if (position.bitboards[Piece::WP] & Self::get_file_mask(sq)).is_empty() {
piece_score += SEMI_OPEN_FILE_SCORE;
}
} else {
if (position.bitboards[Piece::BP] & Self::get_file_mask(sq)).is_empty() {
piece_score += SEMI_OPEN_FILE_SCORE;
}
}
if ((position.bitboards[Piece::WP] | position.bitboards[Piece::BP]) & Self::get_file_mask(sq)).is_empty() {
piece_score += OPEN_FILE_SCORE;
}
} else if piece == Piece::WK || piece == Piece::BK {
if piece == Piece::WK {
if (position.bitboards[Piece::WP] & Self::get_file_mask(sq)).is_empty() {
piece_score += KING_ON_SEMI_OPEN_FILE_SCORE;
}
piece_score += (position.white_occupancy & MoveMasks::get_king_mask(sq)).count_bits() as i16 * KING_ADJACENCY_SCORE;
piece_score -= (position.black_occupancy & MoveMasks::get_king_mask(sq)).count_bits() as i16 * KING_ADJACENCY_SCORE;
} else {
if (position.bitboards[Piece::BP] & Self::get_file_mask(sq)).is_empty() {
piece_score += KING_ON_SEMI_OPEN_FILE_SCORE;
}
piece_score += (position.black_occupancy & MoveMasks::get_king_mask(sq)).count_bits() as i16 * KING_ADJACENCY_SCORE;
piece_score -= (position.white_occupancy & MoveMasks::get_king_mask(sq)).count_bits() as i16 * KING_ADJACENCY_SCORE;
}
}
score += piece_score * piece_color_modifier;
}
#[cfg(feature = "tapered_eval")]
{ score += Self::get_tapered_score(game_phase, position.game_phase_score, opening_score, endgame_score); }
#[cfg(feature = "pseudo_pins")]
{
let wk_square = Square::from(position.bitboards[Piece::WK]);
let bk_square = Square::from(position.bitboards[Piece::BK]);
score -= (MoveMasks::get_bishop_mask_empty_occupancy(wk_square) & position.bitboards[Piece::BB]).count_bits() as i16 * PSEUDO_PIN_SCORE;
score -= (MoveMasks::get_rook_mask_empty_occupancy(wk_square) & position.bitboards[Piece::BR]).count_bits() as i16 * PSEUDO_PIN_SCORE;
score -= (MoveMasks::get_queen_mask_empty_occupancy(wk_square) & position.bitboards[Piece::BQ]).count_bits() as i16 * PSEUDO_PIN_SCORE;
score += (MoveMasks::get_bishop_mask_empty_occupancy(bk_square) & position.bitboards[Piece::WB]).count_bits() as i16 * PSEUDO_PIN_SCORE;
score += (MoveMasks::get_rook_mask_empty_occupancy(bk_square) & position.bitboards[Piece::WR]).count_bits() as i16 * PSEUDO_PIN_SCORE;
score += (MoveMasks::get_queen_mask_empty_occupancy(bk_square) & position.bitboards[Piece::WQ]).count_bits() as i16 * PSEUDO_PIN_SCORE;
}
if position.bitboards[Piece::WB].count_bits() >= 2 {
score += BISHOP_PAIR_SCORE;
}
if position.bitboards[Piece::BB].count_bits() >= 2 {
score -= BISHOP_PAIR_SCORE;
}
if position.in_check(position.side) {
score -= CHECK_SCORE;
}
match position.side {
Color::White => score,
Color::Black => -score,
}
}
}