stellar

UCI Chess engine written in C++20
git clone git://git.dimitrijedobrota.com/stellar.git
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commite26c0125387c4738632abdde53da5266823d04c1
parent03fbb7cf3cd5a47ba4caf020c6d8752d190294a8
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateMon, 19 Sep 2022 19:00:25 +0200

Refactor Bishop and Rook Attack functions

Diffstat:
Msrc/engine.c|+++++++++++++++++++++++++++++-----------------------------------------------------

1 files changed, 38 insertions(+), 70 deletions(-)

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

@@ -51,6 +51,7 @@ char squares[][3]={

// clang-format on
// board moving
typedef U64 (*direction_f)(U64);
U64 soutOne(U64 b) { return b >> 8; }
U64 nortOne(U64 b) { return b << 8; }
U64 eastOne(U64 b) { return (b & notHFile) << 1; }

@@ -170,98 +171,65 @@ U64 mask_king_attacks(int square) {

}
U64 mask_bishop_attacks(int square) {
U64 bitboard = C64(0), attacks = C64(0), tmp;
int tr = square / 8, tf = square % 8, i;
U64 bitboard = C64(0), attacks = C64(0), tmp;
direction_f dir[4] = {noEaOne, noWeOne, soEaOne, soWeOne};
int tr = square / 8, tf = square % 8, i, j;
int len[4] = {MIN(7 - tf, 7 - tr) - 1, MIN(tf, 7 - tr) - 1,
MIN(7 - tf, tr) - 1, MIN(tf, tr) - 1};
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);
for (i = 0; i < 4; i++)
for (j = 0, tmp = bitboard; j < len[i]; j++)
attacks |= tmp = dir[i](tmp);
return attacks;
}
U64 mask_rook_attacks(int square) {
U64 bitboard = C64(0), attacks = C64(0), tmp;
int tr = square / 8, tf = square % 8, i;
U64 bitboard = C64(0), attacks = C64(0), tmp;
direction_f dir[4] = {westOne, soutOne, eastOne, nortOne};
int tr = square / 8, tf = square % 8, i, j;
int len[4] = {tf - 1, tr - 1, 6 - tf, 6 - tr};
bit_set(bitboard, square);
for (i = 0, tmp = bitboard; i < tf - 1; i++)
attacks |= tmp = westOne(tmp);
for (i = 0, tmp = bitboard; i < tr - 1; i++)
attacks |= tmp = soutOne(tmp);
for (i = 0, tmp = bitboard; i < 6 - tf; i++)
attacks |= tmp = eastOne(tmp);
for (i = 0, tmp = bitboard; i < 6 - tr; i++)
attacks |= tmp = nortOne(tmp);
for (i = 0; i < 4; i++)
for (j = 0, tmp = bitboard; j < len[i]; j++)
attacks |= tmp = dir[i](tmp);
return attacks;
}
U64 bishop_attacks_on_the_fly(int square, U64 block) {
U64 bitboard = C64(0), attacks = C64(0), tmp;
int tr = square / 8, tf = square % 8, i;
U64 bitboard = C64(0), attacks = C64(0), tmp;
direction_f dir[4] = {noEaOne, noWeOne, soEaOne, soWeOne};
int tr = square / 8, tf = square % 8, i, j;
int len[4] = {MIN(7 - tf, 7 - tr), MIN(tf, 7 - tr), MIN(7 - tf, tr),
MIN(tf, tr)};
bit_set(bitboard, square);
for (i = 0, tmp = bitboard; i < MIN(7 - tf, 7 - tr); i++) {
attacks |= tmp = noEaOne(tmp);
if (tmp & block)
break;
}
for (i = 0, tmp = bitboard; i < MIN(tf, 7 - tr); i++) {
attacks |= tmp = noWeOne(tmp);
if (tmp & block)
break;
}
for (i = 0, tmp = bitboard; i < MIN(7 - tf, tr); i++) {
attacks |= tmp = soEaOne(tmp);
if (tmp & block)
break;
}
for (i = 0, tmp = bitboard; i < MIN(tf, tr); i++) {
attacks |= tmp = soWeOne(tmp);
if (tmp & block)
break;
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;
}
U64 rook_attacks_on_the_fly(int square, U64 block) {
U64 bitboard = C64(0), attacks = C64(0), tmp;
int tr = square / 8, tf = square % 8, i;
U64 bitboard = C64(0), attacks = C64(0), tmp;
direction_f dir[4] = {westOne, soutOne, eastOne, nortOne};
int tr = square / 8, tf = square % 8, i, j;
int len[4] = {tf, tr, 7 - tf, 7 - tr};
bit_set(bitboard, square);
for (i = 0, tmp = bitboard; i < tf; i++) {
attacks |= tmp = westOne(tmp);
if (tmp & block)
break;
}
for (i = 0, tmp = bitboard; i < tr; i++) {
attacks |= tmp = soutOne(tmp);
if (tmp & block)
break;
}
for (i = 0, tmp = bitboard; i < 7; i++) {
attacks |= tmp = eastOne(tmp);
if (tmp & block)
break;
}
for (i = 0, tmp = bitboard; i < 7; i++) {
attacks |= tmp = nortOne(tmp);
if (tmp & block)
break;
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;
}

@@ -284,6 +252,6 @@ int main(void) {

bit_set(block, d5);
for (int square = 0; square < 64; square++)
bitboard_print(rook_attacks_on_the_fly(square, block));
bitboard_print(mask_rook_attacks(square));
return 0;
}