stellar

UCI Chess engine written in C++20

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

commit	9a599121be77a675f1ff1a1b9254ca2efe143f58
parent	0b4d57ebf8864c0f4276668cf5df89a66cf3ed93
author	Dimitrije Dobrota <mail@dimitrijedobrota.com>
date	Sat, 29 Jul 2023 20:41:20 +0200

Improve naming consistency of Attacks interface

Diffstat:

M	CMakeLists.txt	\|	+-
D	src/attack/CMakeLists.txt	\|	-------
D	src/attack/attack.c	\|	---------------------------------------------------------------------------------
A	src/attacks/CMakeLists.txt	\|	+++++++
A	src/attacks/attacks.c	\|	+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M	src/engine/CMakeLists.txt	\|	+-
M	src/engine/engine.c	\|	++--
D	src/include/attack.h	\|	------------------
A	src/include/attacks.h	\|	++++++++++++++++
M	src/include/piece.h	\|	+-
M	src/perft/CMakeLists.txt	\|	+-
M	src/perft/perft.c	\|	++--
M	src/piece/piece.c	\|	+++++++++++++--------------

13 files changed, 411 insertions(+), 418 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt

@@ -3,7 +3,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

project(

Stellar

VERSION 0.0.2

VERSION 0.0.3

DESCRIPTION "Chess engine written in C"

HOMEPAGE_URL https://git.dimitrijedobrota.com/stellar.git

LANGUAGES C

diff --git a/src/attack/CMakeLists.txt b/src/attack/CMakeLists.txt

@@ -1,7 +0,0 @@

add_library(attack OBJECT

attack.c

)

target_include_directories(attack

PUBLIC "${PROJECT_SOURCE_DIR}/src/include"

)

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

@@ -1,371 +0,0 @@

#include "string.h"

#include "attack.h"

#include "piece.h"

#define UNUSED(x) (void)(x)

// Magic constants

// clang-format off

const int bishop_relevant_bits[64] = {

6, 5, 5, 5, 5, 5, 5, 6,

5, 5, 5, 5, 5, 5, 5, 5,

5, 5, 7, 7, 7, 7, 5, 5,

5, 5, 7, 9, 9, 7, 5, 5,

5, 5, 7, 7, 7, 7, 5, 5,

5, 5, 5, 5, 5, 5, 5, 5,

6, 5, 5, 5, 5, 5, 5, 6,

};

const U64 bishop_magic_numbers[64] = {

C64(0x40040844404084), C64(0x2004208a004208), C64(0x10190041080202),

C64(0x108060845042010), C64(0x581104180800210), C64(0x2112080446200010),

C64(0x1080820820060210), C64(0x3c0808410220200), C64(0x4050404440404),

C64(0x21001420088), C64(0x24d0080801082102), C64(0x1020a0a020400),

C64(0x40308200402), C64(0x4011002100800), C64(0x401484104104005),

C64(0x801010402020200), C64(0x400210c3880100), C64(0x404022024108200),

C64(0x810018200204102), C64(0x4002801a02003), C64(0x85040820080400),

C64(0x810102c808880400), C64(0xe900410884800), C64(0x8002020480840102),

C64(0x220200865090201), C64(0x2010100a02021202), C64(0x152048408022401),

C64(0x20080002081110), C64(0x4001001021004000), C64(0x800040400a011002),

C64(0xe4004081011002), C64(0x1c004001012080), C64(0x8004200962a00220),

C64(0x8422100208500202), C64(0x2000402200300c08), C64(0x8646020080080080),

C64(0x80020a0200100808), C64(0x2010004880111000), C64(0x623000a080011400),

C64(0x42008c0340209202), C64(0x209188240001000), C64(0x400408a884001800),

C64(0x110400a6080400), C64(0x1840060a44020800), C64(0x90080104000041),

C64(0x201011000808101), C64(0x1a2208080504f080), C64(0x8012020600211212),

C64(0x500861011240000), C64(0x180806108200800), C64(0x4000020e01040044),

C64(0x300000261044000a), C64(0x802241102020002), C64(0x20906061210001),

C64(0x5a84841004010310), C64(0x4010801011c04), C64(0xa010109502200),

C64(0x4a02012000), C64(0x500201010098b028), C64(0x8040002811040900),

C64(0x28000010020204), C64(0x6000020202d0240), C64(0x8918844842082200),

C64(0x4010011029020020),

};

const int rook_relevant_bits[64] = {

12, 11, 11, 11, 11, 11, 11, 12,

11, 10, 10, 10, 10, 10, 10, 11,

12, 11, 11, 11, 11, 11, 11, 12,

};

const U64 rook_magic_numbers[64] = {

C64(0x8a80104000800020), C64(0x140002000100040), C64(0x2801880a0017001),

C64(0x100081001000420), C64(0x200020010080420), C64(0x3001c0002010008),

C64(0x8480008002000100), C64(0x2080088004402900), C64(0x800098204000),

C64(0x2024401000200040), C64(0x100802000801000), C64(0x120800800801000),

C64(0x208808088000400), C64(0x2802200800400), C64(0x2200800100020080),

C64(0x801000060821100), C64(0x80044006422000), C64(0x100808020004000),

C64(0x12108a0010204200), C64(0x140848010000802), C64(0x481828014002800),

C64(0x8094004002004100), C64(0x4010040010010802), C64(0x20008806104),

C64(0x100400080208000), C64(0x2040002120081000), C64(0x21200680100081),

C64(0x20100080080080), C64(0x2000a00200410), C64(0x20080800400),

C64(0x80088400100102), C64(0x80004600042881), C64(0x4040008040800020),

C64(0x440003000200801), C64(0x4200011004500), C64(0x188020010100100),

C64(0x14800401802800), C64(0x2080040080800200), C64(0x124080204001001),

C64(0x200046502000484), C64(0x480400080088020), C64(0x1000422010034000),

C64(0x30200100110040), C64(0x100021010009), C64(0x2002080100110004),

C64(0x202008004008002), C64(0x20020004010100), C64(0x2048440040820001),

C64(0x101002200408200), C64(0x40802000401080), C64(0x4008142004410100),

C64(0x2060820c0120200), C64(0x1001004080100), C64(0x20c020080040080),

C64(0x2935610830022400), C64(0x44440041009200), C64(0x280001040802101),

C64(0x2100190040002085), C64(0x80c0084100102001), C64(0x4024081001000421),

C64(0x20030a0244872), C64(0x12001008414402), C64(0x2006104900a0804),

C64(0x1004081002402),

};

// Utility functions

int hash(U64 key, U64 magic, int relevant_bits) {

return (key * magic) >> (64 - relevant_bits);

}

// pseudo random numbers

U32 state = C32(1804289383);

U32 get_random_U32_number() {

U32 number = state;

number ^= number << 13;

number ^= number >> 17;

number ^= number << 5;

return state = number;

}

U64 get_random_U64_number() {

U64 n1, n2, n3, n4;

n1 = (U64)(get_random_U32_number()) & C64(0xFFFF);

n2 = (U64)(get_random_U32_number()) & C64(0xFFFF);

n3 = (U64)(get_random_U32_number()) & C64(0xFFFF);

n4 = (U64)(get_random_U32_number()) & C64(0xFFFF);

return n1 | (n2 << 16) | (n3 << 32) | (n4 << 48);

}

// pawn attack table [side][square]

U64 pawn_attacks[2][64];

// knight attack table [square]

U64 knight_attacks[64];

// king attack table [square]

U64 king_attacks[64];

// bishop attack mask

U64 bishop_masks[64];

// rook attack mask

U64 rook_masks[64];

// bishop attack table [square][occupancies]

U64 bishop_attacks[64][512]; // 256 K

// rook attack table [square][occupancies]

U64 rook_attacks[64][4096]; // 2048K

U64 get_wpawn_attacks(Square square, U64 occupancy){

UNUSED(occupancy);

return pawn_attacks[WHITE][square];

}

U64 get_bpawn_attacks(Square square, U64 occupancy){

UNUSED(occupancy);

return pawn_attacks[BLACK][square];

}

U64 get_knight_attacks(Square square, U64 occupancy){

UNUSED(occupancy);

return knight_attacks[square];

}

U64 get_king_attacks(Square square, U64 occupancy){

UNUSED(occupancy);

return king_attacks[square];

}

U64 get_bishop_attacks(Square square, U64 occupancy){

occupancy &= bishop_masks[square];

occupancy = hash(occupancy, bishop_magic_numbers[square],

bishop_relevant_bits[square]);

return bishop_attacks[square][occupancy];

}

U64 get_rook_attacks(Square square, U64 occupancy){

occupancy &= rook_masks[square];

occupancy =

hash(occupancy, rook_magic_numbers[square], rook_relevant_bits[square]);

return rook_attacks[square][occupancy];

}

U64 get_queen_attacks(Square square, U64 occupancy){

return (get_bishop_attacks(square, occupancy) |

get_rook_attacks(square, occupancy));

}

// generate pawn attack

U64 mask_pawn_attacks(int side, Square square) {

U64 bitboard = C64(0);

bit_set(bitboard, square);

if (side == WHITE)

return noWeOne(bitboard) | noEaOne(bitboard);

else

return soWeOne(bitboard) | soEaOne(bitboard);

}

U64 mask_knight_attacks(Square square) {

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

bit_set(bitboard, square);

tmp = nortOne(nortOne(bitboard));

attacks |= westOne(tmp) | eastOne(tmp);

tmp = soutOne(soutOne(bitboard));

attacks |= westOne(tmp) | eastOne(tmp);

tmp = westOne(westOne(bitboard));

attacks |= soutOne(tmp) | nortOne(tmp);

tmp = eastOne(eastOne(bitboard));

attacks |= soutOne(tmp) | nortOne(tmp);

return attacks;

}

U64 mask_king_attacks(Square square) {

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

bit_set(bitboard, square);

attacks |= westOne(bitboard) | eastOne(bitboard);

attacks |= soutOne(bitboard) | nortOne(bitboard);

attacks |= soEaOne(bitboard) | noEaOne(bitboard);

attacks |= soWeOne(bitboard) | noWeOne(bitboard);

return attacks;

}

U64 mask_slide_attacks(Square square, U64 block, const direction_f dir[4],

int len[4]) {

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

int i, j;

bit_set(bitboard, square);

for (i = 0; i < 4; i++) {

for (j = 0, tmp = bitboard; j < len[i]; j++) {

attacks |= tmp = (dir[i])(tmp);

if (tmp & block)

break;

}

return attacks;

}

const direction_f bishop_direction[4] = {noEaOne, noWeOne, soEaOne, soWeOne};

const direction_f rook_direction[4] = {westOne, soutOne, eastOne, nortOne};

U64 mask_bishop_attacks(Square square) {

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

int len[4] = {MIN(7 - tf, 7 - tr) - 1, MIN(tf, 7 - tr) - 1,

MIN(7 - tf, tr) - 1, MIN(tf, tr) - 1};

return mask_slide_attacks(square, C64(0), bishop_direction, len);

}

U64 mask_rook_attacks(Square square) {

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

int len[4] = {tf - 1, tr - 1, 6 - tf, 6 - tr};

return mask_slide_attacks(square, C64(0), rook_direction, len);

}

U64 bishop_attacks_on_the_fly(Square square, U64 block) {

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

int len[4] = {MIN(7 - tf, 7 - tr), MIN(tf, 7 - tr), MIN(7 - tf, tr),

MIN(tf, tr)};

return mask_slide_attacks(square, block, bishop_direction, len);

}

U64 rook_attacks_on_the_fly(Square square, U64 block) {

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

int len[4] = {tf, tr, 7 - tf, 7 - tr};

return mask_slide_attacks(square, block, rook_direction, len);

}

void init_leapers_attacks(void) {

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

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

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

knight_attacks[square] = mask_knight_attacks(square);

king_attacks[square] = mask_king_attacks(square);

}

U64 set_occupancy(int index, int bits_in_mask, U64 attack_mask) {

U64 occupancy = C64(0);

for (int count = 0; count < bits_in_mask; count++) {

Square square = bit_lsb_index(attack_mask);

bit_pop(attack_mask, square);

if (index & (1 << count))

bit_set(occupancy, square);

}

return occupancy;

}

void init_sliders_attacks_internal(int bishop) {

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

U64 attack_mask;

if (bishop) {

bishop_masks[square] = mask_bishop_attacks(square);

attack_mask = bishop_masks[square];

} else {

rook_masks[square] = mask_rook_attacks(square);

attack_mask = rook_masks[square];

}

int relevant_bits = bit_count(attack_mask);

int occupancy_indicies = 1 << relevant_bits;

for (int index = 0; index < occupancy_indicies; index++) {

U64 occupancy = set_occupancy(index, relevant_bits, attack_mask);

if (bishop) {

int magic_index = (occupancy * bishop_magic_numbers[square]) >>

(64 - bishop_relevant_bits[square]);

bishop_attacks[square][magic_index] =

bishop_attacks_on_the_fly(square, occupancy);

} else {

int magic_index = hash(occupancy, rook_magic_numbers[square],

rook_relevant_bits[square]);

rook_attacks[square][magic_index] =

rook_attacks_on_the_fly(square, occupancy);

}

void init_sliders_attacks(void) {

init_sliders_attacks_internal(0);

init_sliders_attacks_internal(1);

}

// magic numbers

U64 generate_magic_number() {

return get_random_U64_number() & get_random_U64_number() &

get_random_U64_number();

}

U64 find_magic_number(Square square, int relevant_bits, int bishop) {

U64 occupancies[4096], attacks[4096], used_attacks[4096];

U64 attack_mask =

bishop ? mask_bishop_attacks(square) : mask_rook_attacks(square);

int occupancy_indicies = 1 << relevant_bits;

for (int index = 0; index < occupancy_indicies; index++) {

occupancies[index] = set_occupancy(index, relevant_bits, attack_mask);

attacks[index] = bishop

? bishop_attacks_on_the_fly(square, occupancies[index])

: rook_attacks_on_the_fly(square, occupancies[index]);

}

for (int random_count = 0; random_count < 100000000; random_count++) {

U64 magic_number = generate_magic_number();

if (bit_count((attack_mask * magic_number) & C64(0xFF00000000000000)) < 6)

continue;

memset(used_attacks, C64(0), sizeof(used_attacks));

int index, fail;

for (index = 0, fail = 0; !fail && index < occupancy_indicies; index++) {

int magic_index = hash(occupancies[index], magic_number, relevant_bits);

if (used_attacks[magic_index] == C64(0))

used_attacks[magic_index] = attacks[index];

else if (used_attacks[magic_index] != attacks[index])

fail = 1;

}

if (!fail)

return magic_number;

}

return C64(0);

}

void init_attacks(void) {

init_leapers_attacks();

init_sliders_attacks();

}

diff --git a/src/attacks/CMakeLists.txt b/src/attacks/CMakeLists.txt

@@ -0,0 +1,7 @@

add_library(attacks OBJECT

attacks.c

)

target_include_directories(attacks

PUBLIC "${PROJECT_SOURCE_DIR}/src/include"

)

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

@@ -0,0 +1,367 @@

#include "attacks.h"

#include "piece.h" // BLACK, WHITE

#include <string.h>