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3014f14 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 | use crate::position::Position;
use crate::types::{PieceType, Color};
use crate::bitboard::{pop_lsb, EMPTY};
const MG_WEIGHTS: [i32; 7] = [0, 82, 337, 365, 477, 1025, 20000];
const PAWN_PST: [i32; 64] = [
0, 0, 0, 0, 0, 0, 0, 0,
50, 50, 50, 50, 50, 50, 50, 50,
10, 10, 20, 30, 30, 20, 10, 10,
5, 5, 10, 25, 25, 10, 5, 5,
0, 0, 0, 20, 20, 0, 0, 0,
5, -5,-10, 0, 0,-10, -5, 5,
5, 10, 10,-20,-20, 10, 10, 5,
0, 0, 0, 0, 0, 0, 0, 0
];
const KNIGHT_PST: [i32; 64] = [
-50,-40,-30,-30,-30,-30,-40,-50,
-40,-20, 0, 0, 0, 0,-20,-40,
-30, 0, 10, 15, 15, 10, 0,-30,
-30, 5, 15, 20, 20, 15, 5,-30,
-30, 0, 15, 20, 20, 15, 0,-30,
-30, 5, 10, 15, 15, 10, 5,-30,
-40,-20, 0, 5, 5, 0,-20,-40,
-50,-40,-30,-30,-30,-30,-40,-50
];
const BISHOP_PST: [i32; 64] = [
-20,-10,-10,-10,-10,-10,-10,-20,
-10, 0, 0, 0, 0, 0, 0,-10,
-10, 0, 5, 10, 10, 5, 0,-10,
-10, 5, 5, 10, 10, 5, 5,-10,
-10, 0, 10, 10, 10, 10, 0,-10,
-10, 10, 10, 10, 10, 10, 10,-10,
-10, 5, 0, 0, 0, 0, 5,-10,
-20,-10,-10,-10,-10,-10,-10,-20
];
const ROOK_PST: [i32; 64] = [
0, 0, 0, 0, 0, 0, 0, 0,
5, 10, 10, 10, 10, 10, 10, 5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
-5, 0, 0, 0, 0, 0, 0, -5,
0, 0, 0, 5, 5, 0, 0, 0
];
const QUEEN_PST: [i32; 64] = [
-20,-10,-10, -5, -5,-10,-10,-20,
-10, 0, 0, 0, 0, 0, 0,-10,
-10, 0, 5, 5, 5, 5, 0,-10,
-5, 0, 5, 5, 5, 5, 0, -5,
0, 0, 5, 5, 5, 5, 0, -5,
-10, 5, 5, 5, 5, 5, 0,-10,
-10, 0, 5, 0, 0, 0, 0,-10,
-20,-10,-10, -5, -5,-10,-10,-20
];
const KING_MG_PST: [i32; 64] = [
-30,-40,-40,-50,-50,-40,-40,-30,
-30,-40,-40,-50,-50,-40,-40,-30,
-30,-40,-40,-50,-50,-40,-40,-30,
-30,-40,-40,-50,-50,-40,-40,-30,
-20,-30,-30,-40,-40,-30,-30,-20,
-10,-20,-20,-20,-20,-20,-20,-10,
20, 20, 0, 0, 0, 0, 20, 20,
20, 30, 10, 0, 0, 10, 30, 20
];
fn mirror_sq(sq: usize) -> usize {
sq ^ 56
}
fn get_pst_score(p_type: PieceType, sq: usize, is_white: bool) -> i32 {
let index = if is_white { mirror_sq(sq) } else { sq };
match p_type {
PieceType::Pawn => PAWN_PST[index],
PieceType::Knight => KNIGHT_PST[index],
PieceType::Bishop => BISHOP_PST[index],
PieceType::Rook => ROOK_PST[index],
PieceType::Queen => QUEEN_PST[index],
PieceType::King => KING_MG_PST[index],
_ => 0,
}
}
pub fn evaluate(pos: &Position) -> i32 {
let mut score = 0;
for p in 1..=6 {
let p_type: PieceType = unsafe { std::mem::transmute(p as u8) };
let mut w_pieces = pos.pieces[p] & pos.colors[Color::White as usize];
while w_pieces != EMPTY {
let sq = pop_lsb(&mut w_pieces) as usize;
score += MG_WEIGHTS[p];
score += get_pst_score(p_type, sq, true);
}
let mut b_pieces = pos.pieces[p] & pos.colors[Color::Black as usize];
while b_pieces != EMPTY {
let sq = pop_lsb(&mut b_pieces) as usize;
score -= MG_WEIGHTS[p];
score -= get_pst_score(p_type, sq, false);
}
}
if pos.side_to_move == Color::White { score } else { -score }
}
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