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Use None=0 #144

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2 changes: 1 addition & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ sh build-mini.sh

## 4ku-mini Size
```
3,954 bytes
3,941 bytes
```

---
Expand Down
45 changes: 23 additions & 22 deletions src/main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -37,13 +37,13 @@ using namespace std;

enum
{
None,
Pawn,
Knight,
Bishop,
Rook,
Queen,
King,
None
King
};

[[nodiscard]] int64_t now() {
Expand All @@ -57,7 +57,8 @@ using u64 = uint64_t;
struct [[nodiscard]] Position {
array<int, 4> castling = {true, true, true, true};
array<u64, 2> colour = {0xFFFFULL, 0xFFFF000000000000ULL};
array<u64, 6> pieces = {0xFF00000000FF00ULL,
array<u64, 7> pieces = {0x0ULL,
0xFF00000000FF00ULL,
0x4200000000000042ULL,
0x2400000000000024ULL,
0x8100000000000081ULL,
Expand Down Expand Up @@ -154,15 +155,15 @@ vector<TT_Entry> transposition_table;
str += '1' + (flip ? (7 - move.from / 8) : (move.from / 8));
str += 'a' + (move.to % 8);
str += '1' + (flip ? (7 - move.to / 8) : (move.to / 8));
if (move.promo != None) {
str += "\0nbrq\0\0"[move.promo];
if (move.promo) {
str += "\0\0nbrq\0"[move.promo];
}
return str;
}

[[nodiscard]] int piece_on(const Position &pos, const int sq) {
const u64 bb = 1ULL << sq;
for (int i = 0; i < 6; ++i) {
for (int i = 1; i < 7; ++i) {
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Can't this run from 0 to 7? (maybe with a compiled out assert for the fallthrough)

if (pos.pieces[i] & bb) {
return i;
}
Expand All @@ -173,7 +174,7 @@ vector<TT_Entry> transposition_table;
void flip(Position &pos) {
pos.colour[0] = flip(pos.colour[0]);
pos.colour[1] = flip(pos.colour[1]);
for (int i = 0; i < 6; ++i) {
for (int i = 1; i < 7; ++i) {
pos.pieces[i] = flip(pos.pieces[i]);
}
pos.ep = flip(pos.ep);
Expand Down Expand Up @@ -252,7 +253,7 @@ auto makemove(Position &pos, const Move &move) {
}

// Captures
if (captured != None) {
if (captured) {
pos.colour[1] ^= to;
pos.pieces[captured] ^= to;
}
Expand Down Expand Up @@ -348,7 +349,7 @@ void generate_piece_moves(Move *const movelist,
}

const int phases[] = {0, 1, 1, 2, 4, 0};
const int max_material[] = {133, 418, 401, 603, 1262, 0, 0};
const int max_material[] = {0, 133, 418, 401, 603, 1262, 0};
const int material[] = {S(80, 133), S(418, 292), S(401, 328), S(546, 603), S(1262, 1065), 0};
const int psts[][4] = {
{S(-19, 0), S(-1, -2), S(6, 0), S(6, 11)},
Expand Down Expand Up @@ -391,7 +392,7 @@ const int pawn_attacked[] = {S(-64, -14), S(-155, -142)};

// For each piece type
for (int p = 0; p < 6; ++p) {
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Why isn't this loop simply going from 1 to 7, avoiding all the p + 1? I'd compute that once into a var for the eval array indexing, if only the avoid the eyebleed this is now.

auto copy = pos.colour[0] & pos.pieces[p];
auto copy = pos.colour[0] & pos.pieces[p + 1];
while (copy) {
phase += phases[p];

Expand Down Expand Up @@ -424,7 +425,7 @@ const int pawn_attacked[] = {S(-64, -14), S(-155, -142)};
score += pawn_attacked[c];
}

if (p == Pawn) {
if (p + 1 == Pawn) {
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Yeeaargh.

// Passed pawns
u64 blockers = 0x101010101010101ULL << sq;
blockers = nw(blockers) | ne(blockers);
Expand All @@ -448,7 +449,7 @@ const int pawn_attacked[] = {S(-64, -14), S(-155, -142)};
if ((north(piece_bb) | north(north(piece_bb))) & pawns[0]) {
score += pawn_doubled;
}
} else if (p == Rook) {
} else if (p + 1 == Rook) {
// Rook on open or semi-open files
const u64 file_bb = 0x101010101010101ULL << file;
if (!(file_bb & pawns[0])) {
Expand All @@ -463,7 +464,7 @@ const int pawn_attacked[] = {S(-64, -14), S(-155, -142)};
if (rank >= 6) {
score += rook_rank78;
}
} else if (p == King && piece_bb & 0xE7) {
} else if (p + 1 == King && piece_bb & 0xE7) {
const u64 shield = file < 3 ? 0x700 : 0xE000;
score += count(shield & pawns[0]) * king_shield[0];
score += count(north(shield) & pawns[0]) * king_shield[1];
Expand All @@ -487,18 +488,18 @@ const int pawn_attacked[] = {S(-64, -14), S(-155, -142)};
u64 hash = pos.flipped;

// Pieces
for (int p = Pawn; p < None; p++) {
for (int p = 1; p < 7; p++) {
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This could still use symbols.

u64 copy = pos.pieces[p] & pos.colour[0];
while (copy) {
const int sq = lsb(copy);
copy &= copy - 1;
hash ^= keys[p * 64 + sq];
hash ^= keys[(p - 1) * 64 + sq];
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You can cheat and make keys bigger to avoid the -1.

}
copy = pos.pieces[p] & pos.colour[1];
while (copy) {
const int sq = lsb(copy);
copy &= copy - 1;
hash ^= keys[(p + 6) * 64 + sq];
hash ^= keys[(p + 5) * 64 + sq];
}
}

Expand Down Expand Up @@ -638,8 +639,8 @@ int alphabeta(Position &pos,
if (i == !(no_move == tt_move)) {
for (int j = 0; j < num_moves; ++j) {
const int capture = piece_on(pos, moves[j].to);
if (capture != None) {
move_scores[j] = (capture + 1) * (1LL << 54);
if (capture) {
move_scores[j] = capture * (1LL << 54);
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} else if (moves[j] == stack[ply].killer) {
move_scores[j] = 1LL << 50;
} else {
Expand Down Expand Up @@ -711,7 +712,7 @@ int alphabeta(Position &pos,
hash_history);
} else {
// Late move reduction
int reduction = depth > 2 && num_moves_evaluated > 4 && piece_on(pos, move.to) == None
int reduction = depth > 2 && num_moves_evaluated > 4 && !piece_on(pos, move.to)
? 1 + num_moves_evaluated / 14 + depth / 17 + (alpha == beta - 1) - improving +
(hh_table[pos.flipped][move.from][move.to] < 0) -
(hh_table[pos.flipped][move.from][move.to] > 0)
Expand Down Expand Up @@ -749,7 +750,7 @@ int alphabeta(Position &pos,
}

num_moves_evaluated++;
if (piece_on(pos, move.to) == None) {
if (!piece_on(pos, move.to)) {
stack[ply].quiets_evaluated[num_quiets_evaluated] = move;
num_quiets_evaluated++;
}
Expand All @@ -771,7 +772,7 @@ int alphabeta(Position &pos,

if (alpha >= beta) {
tt_flag = 1; // Beta flag
if (piece_on(pos, move.to) == None) {
if (!piece_on(pos, move.to)) {
hh_table[pos.flipped][move.from][move.to] += depth * depth;
for (int j = 0; j < num_quiets_evaluated - 1; ++j) {
hh_table[pos.flipped][stack[ply].quiets_evaluated[j].from][stack[ply].quiets_evaluated[j].to] -=
Expand Down Expand Up @@ -1176,7 +1177,7 @@ int main(
const int num_moves = movegen(pos, moves, false);
for (int i = 0; i < num_moves; ++i) {
if (word == move_str(moves[i], pos.flipped)) {
if (piece_on(pos, moves[i].to) != None || piece_on(pos, moves[i].from) == Pawn) {
if (piece_on(pos, moves[i].to) || piece_on(pos, moves[i].from) == Pawn) {
hash_history.clear();
} else {
hash_history.emplace_back(get_hash(pos));
Expand Down