Stockfish/src/types.h

/*
  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
  Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)

  Stockfish is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Stockfish is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef TYPES_H_INCLUDED
    #define TYPES_H_INCLUDED

// When compiling with provided Makefile (e.g. for Linux and OSX), configuration
// is done automatically. To get started type 'make help'.
//
// When Makefile is not used (e.g. with Microsoft Visual Studio) some switches
// need to be set manually:
//
// -DNDEBUG      | Disable debugging mode. Always use this for release.
//
// -DNO_PREFETCH | Disable use of prefetch asm-instruction. You may need this to
//               | run on some very old machines.
//
// -DUSE_POPCNT  | Add runtime support for use of popcnt asm-instruction. Works
//               | only in 64-bit mode and requires hardware with popcnt support.
//
// -DUSE_PEXT    | Add runtime support for use of pext asm-instruction. Works
//               | only in 64-bit mode and requires hardware with pext support.

    #include <cassert>
    #include <cstdint>

    #if defined(_MSC_VER)
        // Disable some silly and noisy warnings from MSVC compiler
        #pragma warning(disable: 4127)  // Conditional expression is constant
        #pragma warning(disable: 4146)  // Unary minus operator applied to unsigned type
        #pragma warning(disable: 4800)  // Forcing value to bool 'true' or 'false'
    #endif

// Predefined macros hell:
//
// __GNUC__                Compiler is GCC, Clang or ICX
// __clang__               Compiler is Clang or ICX
// __INTEL_LLVM_COMPILER   Compiler is ICX
// _MSC_VER                Compiler is MSVC
// _WIN32                  Building on Windows (any)
// _WIN64                  Building on Windows 64 bit

    #if defined(__GNUC__) && (__GNUC__ < 9 || (__GNUC__ == 9 && __GNUC_MINOR__ <= 2)) \
      && defined(_WIN32) && !defined(__clang__)
        #define ALIGNAS_ON_STACK_VARIABLES_BROKEN
    #endif

    #define ASSERT_ALIGNED(ptr, alignment) assert(reinterpret_cast<uintptr_t>(ptr) % alignment == 0)

    #if defined(_WIN64) && defined(_MSC_VER)  // No Makefile used
        #include <intrin.h>                   // Microsoft header for _BitScanForward64()
        #define IS_64BIT
    #endif

    #if defined(USE_POPCNT) && defined(_MSC_VER)
        #include <nmmintrin.h>  // Microsoft header for _mm_popcnt_u64()
    #endif

    #if !defined(NO_PREFETCH) && defined(_MSC_VER)
        #include <xmmintrin.h>  // Microsoft header for _mm_prefetch()
    #endif

    #if defined(USE_PEXT)
        #include <immintrin.h>  // Header for _pext_u64() intrinsic
        #define pext(b, m) _pext_u64(b, m)
    #else
        #define pext(b, m) 0
    #endif

namespace Stockfish {

    #ifdef USE_POPCNT
constexpr bool HasPopCnt = true;
    #else
constexpr bool HasPopCnt = false;
    #endif

    #ifdef USE_PEXT
constexpr bool HasPext = true;
    #else
constexpr bool HasPext = false;
    #endif

    #ifdef IS_64BIT
constexpr bool Is64Bit = true;
    #else
constexpr bool Is64Bit = false;
    #endif

using Key      = uint64_t;
using Bitboard = uint64_t;

constexpr int MAX_MOVES = 256;
constexpr int MAX_PLY   = 246;

// A move needs 16 bits to be stored
//
// bit  0- 5: destination square (from 0 to 63)
// bit  6-11: origin square (from 0 to 63)
// bit 12-13: promotion piece type - 2 (from KNIGHT-2 to QUEEN-2)
// bit 14-15: special move flag: promotion (1), en passant (2), castling (3)
// NOTE: en passant bit is set only when a pawn can be captured
//
// Special cases are MOVE_NONE and MOVE_NULL. We can sneak these in because in
// any normal move destination square is always different from origin square
// while MOVE_NONE and MOVE_NULL have the same origin and destination square.

enum Move : int {
    MOVE_NONE,
    MOVE_NULL = 65
};

enum MoveType {
    NORMAL,
    PROMOTION  = 1 << 14,
    EN_PASSANT = 2 << 14,
    CASTLING   = 3 << 14
};

enum Color {
    WHITE,
    BLACK,
    COLOR_NB = 2
};

enum CastlingRights {
    NO_CASTLING,
    WHITE_OO,
    WHITE_OOO = WHITE_OO << 1,
    BLACK_OO  = WHITE_OO << 2,
    BLACK_OOO = WHITE_OO << 3,

    KING_SIDE      = WHITE_OO | BLACK_OO,
    QUEEN_SIDE     = WHITE_OOO | BLACK_OOO,
    WHITE_CASTLING = WHITE_OO | WHITE_OOO,
    BLACK_CASTLING = BLACK_OO | BLACK_OOO,
    ANY_CASTLING   = WHITE_CASTLING | BLACK_CASTLING,

    CASTLING_RIGHT_NB = 16
};

enum Bound {
    BOUND_NONE,
    BOUND_UPPER,
    BOUND_LOWER,
    BOUND_EXACT = BOUND_UPPER | BOUND_LOWER
};

enum Value : int {
    VALUE_ZERO     = 0,
    VALUE_DRAW     = 0,
    VALUE_NONE     = 32002,
    VALUE_INFINITE = 32001,

    VALUE_MATE             = 32000,
    VALUE_MATE_IN_MAX_PLY  = VALUE_MATE - MAX_PLY,
    VALUE_MATED_IN_MAX_PLY = -VALUE_MATE_IN_MAX_PLY,

    VALUE_TB                 = VALUE_MATE_IN_MAX_PLY - 1,
    VALUE_TB_WIN_IN_MAX_PLY  = VALUE_TB - MAX_PLY,
    VALUE_TB_LOSS_IN_MAX_PLY = -VALUE_TB_WIN_IN_MAX_PLY,

    // In the code, we make the assumption that these values
    // are such that non_pawn_material() can be used to uniquely
    // identify the material on the board.
    PawnValue   = 208,
    KnightValue = 781,
    BishopValue = 825,
    RookValue   = 1276,
    QueenValue  = 2538,
};

// clang-format off
enum PieceType {
    NO_PIECE_TYPE, PAWN, KNIGHT, BISHOP, ROOK, QUEEN, KING,
    ALL_PIECES = 0,
    PIECE_TYPE_NB = 8
};

enum Piece {
    NO_PIECE,
    W_PAWN = PAWN,     W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING,
    B_PAWN = PAWN + 8, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING,
    PIECE_NB = 16
};
// clang-format on

constexpr Value PieceValue[PIECE_NB] = {
  VALUE_ZERO, PawnValue, KnightValue, BishopValue, RookValue, QueenValue, VALUE_ZERO, VALUE_ZERO,
  VALUE_ZERO, PawnValue, KnightValue, BishopValue, RookValue, QueenValue, VALUE_ZERO, VALUE_ZERO};

using Depth = int;

enum : int {
    DEPTH_QS_CHECKS    = 0,
    DEPTH_QS_NO_CHECKS = -1,

    DEPTH_NONE = -6,

    DEPTH_OFFSET = -7  // value used only for TT entry occupancy check
};

// clang-format off
enum Square : int {
    SQ_A1, SQ_B1, SQ_C1, SQ_D1, SQ_E1, SQ_F1, SQ_G1, SQ_H1,
    SQ_A2, SQ_B2, SQ_C2, SQ_D2, SQ_E2, SQ_F2, SQ_G2, SQ_H2,
    SQ_A3, SQ_B3, SQ_C3, SQ_D3, SQ_E3, SQ_F3, SQ_G3, SQ_H3,
    SQ_A4, SQ_B4, SQ_C4, SQ_D4, SQ_E4, SQ_F4, SQ_G4, SQ_H4,
    SQ_A5, SQ_B5, SQ_C5, SQ_D5, SQ_E5, SQ_F5, SQ_G5, SQ_H5,
    SQ_A6, SQ_B6, SQ_C6, SQ_D6, SQ_E6, SQ_F6, SQ_G6, SQ_H6,
    SQ_A7, SQ_B7, SQ_C7, SQ_D7, SQ_E7, SQ_F7, SQ_G7, SQ_H7,
    SQ_A8, SQ_B8, SQ_C8, SQ_D8, SQ_E8, SQ_F8, SQ_G8, SQ_H8,
    SQ_NONE,

    SQUARE_ZERO = 0,
    SQUARE_NB   = 64
};
// clang-format on

enum Direction : int {
    NORTH = 8,
    EAST  = 1,
    SOUTH = -NORTH,
    WEST  = -EAST,

    NORTH_EAST = NORTH + EAST,
    SOUTH_EAST = SOUTH + EAST,
    SOUTH_WEST = SOUTH + WEST,
    NORTH_WEST = NORTH + WEST
};

enum File : int {
    FILE_A,
    FILE_B,
    FILE_C,
    FILE_D,
    FILE_E,
    FILE_F,
    FILE_G,
    FILE_H,
    FILE_NB
};

enum Rank : int {
    RANK_1,
    RANK_2,
    RANK_3,
    RANK_4,
    RANK_5,
    RANK_6,
    RANK_7,
    RANK_8,
    RANK_NB
};

// Keep track of what a move changes on the board (used by NNUE)
struct DirtyPiece {

    // Number of changed pieces
    int dirty_num;

    // Max 3 pieces can change in one move. A promotion with capture moves
    // both the pawn and the captured piece to SQ_NONE and the piece promoted
    // to from SQ_NONE to the capture square.
    Piece piece[3];

    // From and to squares, which may be SQ_NONE
    Square from[3];
    Square to[3];
};

    #define ENABLE_BASE_OPERATORS_ON(T) \
        constexpr T operator+(T d1, int d2) { return T(int(d1) + d2); } \
        constexpr T operator-(T d1, int d2) { return T(int(d1) - d2); } \
        constexpr T operator-(T d) { return T(-int(d)); } \
        inline T&   operator+=(T& d1, int d2) { return d1 = d1 + d2; } \
        inline T&   operator-=(T& d1, int d2) { return d1 = d1 - d2; }

    #define ENABLE_INCR_OPERATORS_ON(T) \
        inline T& operator++(T& d) { return d = T(int(d) + 1); } \
        inline T& operator--(T& d) { return d = T(int(d) - 1); }

    #define ENABLE_FULL_OPERATORS_ON(T) \
        ENABLE_BASE_OPERATORS_ON(T) \
        constexpr T   operator*(int i, T d) { return T(i * int(d)); } \
        constexpr T   operator*(T d, int i) { return T(int(d) * i); } \
        constexpr T   operator/(T d, int i) { return T(int(d) / i); } \
        constexpr int operator/(T d1, T d2) { return int(d1) / int(d2); } \
        inline T&     operator*=(T& d, int i) { return d = T(int(d) * i); } \
        inline T&     operator/=(T& d, int i) { return d = T(int(d) / i); }

ENABLE_FULL_OPERATORS_ON(Value)
ENABLE_FULL_OPERATORS_ON(Direction)

ENABLE_INCR_OPERATORS_ON(PieceType)
ENABLE_INCR_OPERATORS_ON(Square)
ENABLE_INCR_OPERATORS_ON(File)
ENABLE_INCR_OPERATORS_ON(Rank)

    #undef ENABLE_FULL_OPERATORS_ON
    #undef ENABLE_INCR_OPERATORS_ON
    #undef ENABLE_BASE_OPERATORS_ON

// Additional operators to add a Direction to a Square
constexpr Square operator+(Square s, Direction d) { return Square(int(s) + int(d)); }
constexpr Square operator-(Square s, Direction d) { return Square(int(s) - int(d)); }
inline Square&   operator+=(Square& s, Direction d) { return s = s + d; }
inline Square&   operator-=(Square& s, Direction d) { return s = s - d; }

// Toggle color
constexpr Color operator~(Color c) { return Color(c ^ BLACK); }

// Swap A1 <-> A8
constexpr Square flip_rank(Square s) { return Square(s ^ SQ_A8); }

// Swap A1 <-> H1
constexpr Square flip_file(Square s) { return Square(s ^ SQ_H1); }

// Swap color of piece B_KNIGHT <-> W_KNIGHT
constexpr Piece operator~(Piece pc) { return Piece(pc ^ 8); }

constexpr CastlingRights operator&(Color c, CastlingRights cr) {
    return CastlingRights((c == WHITE ? WHITE_CASTLING : BLACK_CASTLING) & cr);
}

constexpr Value mate_in(int ply) { return VALUE_MATE - ply; }

constexpr Value mated_in(int ply) { return -VALUE_MATE + ply; }

constexpr Square make_square(File f, Rank r) { return Square((r << 3) + f); }

constexpr Piece make_piece(Color c, PieceType pt) { return Piece((c << 3) + pt); }

constexpr PieceType type_of(Piece pc) { return PieceType(pc & 7); }

inline Color color_of(Piece pc) {
    assert(pc != NO_PIECE);
    return Color(pc >> 3);
}

constexpr bool is_ok(Move m) { return m != MOVE_NONE && m != MOVE_NULL; }

constexpr bool is_ok(Square s) { return s >= SQ_A1 && s <= SQ_H8; }

constexpr File file_of(Square s) { return File(s & 7); }

constexpr Rank rank_of(Square s) { return Rank(s >> 3); }

constexpr Square relative_square(Color c, Square s) { return Square(s ^ (c * 56)); }

constexpr Rank relative_rank(Color c, Rank r) { return Rank(r ^ (c * 7)); }

constexpr Rank relative_rank(Color c, Square s) { return relative_rank(c, rank_of(s)); }

constexpr Direction pawn_push(Color c) { return c == WHITE ? NORTH : SOUTH; }

constexpr Square from_sq(Move m) {
    assert(is_ok(m));
    return Square((m >> 6) & 0x3F);
}

constexpr Square to_sq(Move m) {
    assert(is_ok(m));
    return Square(m & 0x3F);
}

constexpr int from_to(Move m) { return m & 0xFFF; }

constexpr MoveType type_of(Move m) { return MoveType(m & (3 << 14)); }

constexpr PieceType promotion_type(Move m) { return PieceType(((m >> 12) & 3) + KNIGHT); }

constexpr Move make_move(Square from, Square to) { return Move((from << 6) + to); }

template<MoveType T>
constexpr Move make(Square from, Square to, PieceType pt = KNIGHT) {
    return Move(T + ((pt - KNIGHT) << 12) + (from << 6) + to);
}

// Based on a congruential pseudo-random number generator
constexpr Key make_key(uint64_t seed) {
    return seed * 6364136223846793005ULL + 1442695040888963407ULL;
}

}  // namespace Stockfish

#endif  // #ifndef TYPES_H_INCLUDED

#include "tune.h"  // Global visibility to tuning setup