stellar

UCI Chess engine written in C++20

git clone git://git.dimitrijedobrota.com/stellar.git

commit	29568808a50e6f13021dcc79acdfc864fbcdefea
parent	a1e1fde71226015465fd0dacbf438af066a8f5c7
author	Dimitrije Dobrota <mail@dimitrijedobrota.com>
date	Mon, 19 Sep 2022 18:09:53 +0200

Bishop attack mask

Diffstat:

src/engine.c

++++++++++++++++++++++++++----

1 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/engine.c b/src/engine.c

@@ -8,18 +8,22 @@

/* DEFINITIONS */

// useful macros

#define MAX(a, b) ((a > b) ? a : b)

#define MIN(a, b) ((a < b) ? a : b)

typedef unsigned long long U64; // define bitboard data type

#define C64(constantU64) constantU64##ULL // define shorthand for constants

// usefull bit patterns

// useful bit patterns

const U64 universe = C64(0xffffffffffffffff); //

const U64 notAFile = C64(0xfefefefefefefefe); // ~0x0101010101010101

const U64 notHFile = C64(0x7f7f7f7f7f7f7f7f); // ~0x8080808080808080

// useful bit operations

#define bit_get(bitboard, square) ((bitboard >> square) & C64(1))

#define bit_set(bitboard, square) (bitboard |= C64(1) << square)

#define bit_pop(bitboard, square) (bitboard &= ~(C64(1) << square))

#define bit_get(bitboard, square) (((bitboard) >> (square)) & C64(1))

#define bit_set(bitboard, square) ((bitboard) |= C64(1) << (square))

#define bit_pop(bitboard, square) ((bitboard) &= ~(C64(1) << (square)))

// squares

// clang-format off

@@ -165,6 +169,24 @@ U64 mask_king_attacks(int square) {

return attacks;

}

U64 mask_bishup_attacks(int square) {

U64 bitboard = C64(0), attacks = C64(0), tmp;

int tr = square / 8, tf = square % 8, i;

bit_set(bitboard, square);

for (i = 0, tmp = bitboard; i < MIN(7 - tf, 7 - tr) - 1; i++)

attacks |= tmp = noEaOne(tmp);

for (i = 0, tmp = bitboard; i < MIN(tf, 7 - tr) - 1; i++)

attacks |= tmp = noWeOne(tmp);

for (i = 0, tmp = bitboard; i < MIN(7 - tf, tr) - 1; i++)

attacks |= tmp = soEaOne(tmp);

for (i = 0, tmp = bitboard; i < MIN(tf, tr) - 1; i++)

attacks |= tmp = soWeOne(tmp);

return attacks;

}

void init_leapers_attacks(void) {

for (int square = 0; square < 64; square++) {

pawn_attacks[WHITE][square] = mask_pawn_attacks(WHITE, square);