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refactor: (bb64)occupied -> ~(Bb64)PIECE_EMPTY

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This commit is contained in:
Ole Morud
2026-01-07 20:17:55 +01:00
parent 5a5a392c8b
commit bb3d99b011
9 changed files with 71 additions and 83 deletions
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4
board_print.h
View File

@@ -197,10 +197,6 @@ static void board_print(struct pos const* pos, struct move* move, FILE* out, boo
bg = (i+j) % 2 ? 45 : 43;
}
if ((pos->occupied[SIDE_WHITE] | pos->occupied[SIDE_BLACK]) & MASK_FROM_SQ(n)) {
bg += 60; /* make bright */
}
fprintf(out, "\033[%d;%dm", fg, bg);
if (buf[i][j]) {

17
chess-worker.js
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@@ -2,25 +2,24 @@ let exports;
async function init() {
const resp = await fetch("./chess.wasm");
if (!resp.ok) {
throw new Error("fetch wasm failed ${resp.status} ${resp.statusText}");
}
const { instance } =
await WebAssembly.instantiateStreaming(resp, {});
if (!resp.ok) throw new Error(`fetch wasm failed ${resp.status} ${resp.statusText}`);
const { instance } = await WebAssembly.instantiateStreaming(resp, {});
exports = instance.exports;
}
await init();
self.postMessage({ type: "ready" });
self.onmessage = (e) => {
const { id, method, args = [] } = e.data;
try {
const value = exports[method](...args);
let value;
value = exports[method](...args);
self.postMessage({ id, ok: true, value });
} catch (err) {
self.postMessage({ id, ok: false, error: String(err?.message ?? err) });
self.postMessage({
id, ok: false, error: String(err?.message ?? err)
});
}
};

12
engine-attack-sets.h
View File

@@ -91,7 +91,7 @@ static Bb64 diagonals(Bb64 p)
* ==================
*
* All piece attack functions rely on the caller masking their own pieces.
* e.g. `knight_attacks(knights) & ~our_occupied`
* e.g. `knight_attacks(knights) & empty`
* */
static Bb64 knight_attacks(Bb64 p)
@@ -522,7 +522,7 @@ static Bb64 attacks_to(struct pos const* pos,
Bb64 pretend_occupied,
Bb64 pretend_empty)
{
Bb64 const occ_orig = pos->occupied[SIDE_WHITE] | pos->occupied[SIDE_BLACK];
Bb64 const occ_orig = ~(pos->pieces[SIDE_WHITE][PIECE_EMPTY] & pos->pieces[SIDE_BLACK][PIECE_EMPTY]);
Bb64 const occ = (occ_orig & ~pretend_empty) | pretend_occupied;
Bb64 const* pw = pos->pieces[SIDE_WHITE];
@@ -563,15 +563,15 @@ static
Bb64 checkers(struct pos const* pos, Side8 us)
{
/* TODO: specialize */
return attacks_to(pos, pos->pieces[us][PIECE_KING], 0ULL, 0ULL) & ~pos->occupied[us];
return attacks_to(pos, pos->pieces[us][PIECE_KING], 0ULL, 0ULL) & pos->pieces[us][PIECE_EMPTY];
}
static
Bb64 pinning_lines_to_target(struct pos const* pos, Side8 us, Sq8 tsq)
{
Side8 const them = other_side(us);
Bb64 const our_occ = pos->occupied[us];
Bb64 const their_occ = pos->occupied[them];
Bb64 const our_occ = ~pos->pieces[us][PIECE_EMPTY];
Bb64 const their_occ = ~pos->pieces[them][PIECE_EMPTY];
Bb64 const* p = pos->pieces[them];
Bb64 const bqs = p[PIECE_QUEEN] | p[PIECE_BISHOP];
@@ -595,7 +595,7 @@ Bb64 pinning_lines_to_target(struct pos const* pos, Side8 us, Sq8 tsq)
static
Bb64 all_threats_from_side(struct pos const * pos, Side8 who)
{
Bb64 const occ = pos->occupied[SIDE_WHITE] | pos->occupied[SIDE_BLACK];
Bb64 const occ = ~(pos->pieces[SIDE_WHITE][PIECE_EMPTY] & pos->pieces[SIDE_BLACK][PIECE_EMPTY]);
Bb64 const* p = pos->pieces[who];
Bb64 t = 0ULL;

39
engine-board.h
View File

@@ -12,7 +12,6 @@ struct board {
Side8 moving_side;
bool castling_illegal[SIDE_COUNT][CASTLE_COUNT];
Bb64 ep_targets;
Bb64 occupied[SIDE_COUNT];
int halfmoves; /* FIXME: this duplicates the hist.length value */
int fullmoves;
@@ -44,6 +43,7 @@ struct board {
.fullmoves = 1, \
.pieces = { \
[SIDE_WHITE] = { \
[PIECE_EMPTY] = RANK_MASK_3 | RANK_MASK_4 | RANK_MASK_5 | RANK_MASK_6 | RANK_MASK_7 | RANK_MASK_8, \
[PIECE_PAWN] = RANK_MASK_2, \
[PIECE_ROOK] = SQMASK_A1 | SQMASK_H1, \
[PIECE_KNIGHT] = SQMASK_B1 | SQMASK_G1, \
@@ -52,6 +52,7 @@ struct board {
[PIECE_KING] = SQMASK_E1, \
}, \
[SIDE_BLACK] = { \
[PIECE_EMPTY] = RANK_MASK_1 | RANK_MASK_2 | RANK_MASK_3 | RANK_MASK_4 | RANK_MASK_5 | RANK_MASK_6, \
[PIECE_PAWN] = RANK_MASK_7, \
[PIECE_ROOK] = SQMASK_A8 | SQMASK_H8, \
[PIECE_KNIGHT] = SQMASK_B8 | SQMASK_G8, \
@@ -60,16 +61,6 @@ struct board {
[PIECE_KING] = SQMASK_E8, \
} \
}, \
.occupied = { \
[SIDE_WHITE] = \
RANK_MASK_2 | SQMASK_A1 | SQMASK_H1 | \
SQMASK_B1 | SQMASK_G1 | SQMASK_C1 | \
SQMASK_F1 | SQMASK_D1 | SQMASK_E1, \
[SIDE_BLACK] = \
RANK_MASK_7 | SQMASK_A8 | SQMASK_H8 | \
SQMASK_B8 | SQMASK_G8| SQMASK_C8 | \
SQMASK_F8| SQMASK_D8| SQMASK_E8, \
}, \
.hash = ~0ULL, \
}, \
.mailbox = { \
@@ -156,13 +147,20 @@ static bool board_load_fen_unsafe(struct board* b, char const* fen_str)
struct piece_side const p = piece_and_side_from_char[(uint8_t)ch];
Bb64 const sq_mask = MASK_FROM_RF(ri, fi);
b->pos.pieces[p.side][p.piece] |= sq_mask;
b->pos.occupied[p.side] |= sq_mask;
b->pos.pieces[p.side][PIECE_EMPTY] &= ~sq_mask;
b->mailbox[SQ_FROM_RF(ri, fi)] = p.piece;
}
}
(void)BUF_GETCHAR(fen); /* discard '/' or ' ' */
}
b->pos.pieces[SIDE_WHITE][PIECE_EMPTY] = ~0ULL;
b->pos.pieces[SIDE_BLACK][PIECE_EMPTY] = ~0ULL;
for (Piece8 p = PIECE_BEGIN; p < PIECE_COUNT; ++p) {
b->pos.pieces[SIDE_WHITE][PIECE_EMPTY] &= ~b->pos.pieces[SIDE_WHITE][p];
b->pos.pieces[SIDE_BLACK][PIECE_EMPTY] &= ~b->pos.pieces[SIDE_BLACK][p];
}
{ /* active color */
char const ch = BUF_GETCHAR(fen);
if (ch == 'w') {
@@ -238,13 +236,6 @@ enum move_result {
MR_CHECKMATE,
};
struct move_undo {
Piece8 captured_piece;
Piece8 moved_piece;
Sq8 captured_square;
Sq8 moved_square;
};
/* does not check validity */
static enum move_result move_piece(struct pos* restrict pos,
Side8 us,
@@ -252,8 +243,6 @@ static enum move_result move_piece(struct pos* restrict pos,
Piece8 mailbox[restrict static SQ_COUNT],
struct move move)
{
struct move_undo undo;
//Side8 const us = pos->moving_side;
Side8 const them = other_side(us);
@@ -277,7 +266,7 @@ static enum move_result move_piece(struct pos* restrict pos,
do { \
Bb64 const x = MASK_FROM_SQ(from) | MASK_FROM_SQ(to); \
pos->pieces[side][piece] ^= x; \
pos->occupied[side] ^= x; \
pos->pieces[side][PIECE_EMPTY] ^= x; \
pos->hash = tt_hash_update(pos->hash, from, side, piece); \
pos->hash = tt_hash_update(pos->hash, to, side, piece); \
mailbox[to] = piece; \
@@ -288,7 +277,7 @@ static enum move_result move_piece(struct pos* restrict pos,
do { \
Bb64 const x = MASK_FROM_SQ(at); \
pos->pieces[owner][piece] &= ~x; \
pos->occupied[owner] &= ~x; \
pos->pieces[owner][PIECE_EMPTY] |= x; \
pos->hash = tt_hash_update(pos->hash, at, owner, piece); \
hist->length = 0; \
pos->halfmoves = 0; \
@@ -298,7 +287,7 @@ static enum move_result move_piece(struct pos* restrict pos,
do { \
Bb64 const x = MASK_FROM_SQ(at); \
pos->pieces[owner][piece] |= x; \
pos->occupied[owner] |= x; \
pos->pieces[owner][PIECE_EMPTY] &= ~x; \
pos->hash = tt_hash_update(pos->hash, at, owner, piece); \
mailbox[at] = piece; \
pos->halfmoves = 0; \
@@ -325,7 +314,7 @@ static enum move_result move_piece(struct pos* restrict pos,
else {
POS_MOVE(us, from_piece, move.from, move.to);
/* capture */
if (to_mask & pos->occupied[them]) {
if (to_mask & ~pos->pieces[them][PIECE_EMPTY]) {
POS_REMOVE(them, to_piece, move.to);
}

28
engine-move-generation.h
View File

@@ -22,23 +22,7 @@ struct move move_make(struct pos const* restrict pos,
(void)piece;
(void)pos;
(void)add_attr;
#if 0
Side8 const us = pos->moving_side;
Side8 const them = other_side(us);
Bb64 const their_occ = pos->occupied[them];
Bb64 const tomask = MASK_FROM_SQ(to);
Bb64 const finishline = (us == SIDE_WHITE ? RANK_MASK_8 : RANK_MASK_1);
uint8_t attr = 0ULL;
#define MASK_IF8(x) ((~(uint8_t)0U) + (uint8_t)!(x))
attr |= MATTR_CAPTURE & MASK_IF8(tomask & their_occ);
attr |= MATTR_CAPTURE & MASK_IF8((piece == PIECE_PAWN) && tomask & pos->ep_targets);
attr |= MATTR_PROMOTE & MASK_IF8((piece == PIECE_PAWN) && (tomask & finishline));
attr |= add_attr;
#undef MASK_IF8
return (struct move){.from = from, .to = to, .attr = attr};
#endif
return (struct move){.from = from, .to = to, .attr = add_attr};
}
#define MOVE_MAX 128
@@ -63,8 +47,8 @@ static void all_pseudolegal_from_piece(struct pos const* restrict pos,
Side8 them = other_side(us);
Bb64 const our_occ = pos->occupied[us];
Bb64 const all_occ = pos->occupied[SIDE_WHITE] | pos->occupied[SIDE_BLACK];
Bb64 const our_occ = ~pos->pieces[us][PIECE_EMPTY];
Bb64 const all_occ = ~(pos->pieces[SIDE_WHITE][PIECE_EMPTY] & pos->pieces[SIDE_BLACK][PIECE_EMPTY]);
if (type == MG_CHECKS) {
allowed &= non_pawn_piece_attacks(piece, pos->pieces[them][PIECE_KING], all_occ);
@@ -93,7 +77,7 @@ static void all_pseudolegal_pawn_moves_##side(struct pos const* restrict pos,\
size_t* restrict out_count,\
struct move out[restrict static MOVE_MAX])\
{\
Bb64 const all_occ = pos->occupied[SIDE_WHITE] | pos->occupied[SIDE_BLACK];\
Bb64 const all_occ = ~(pos->pieces[SIDE_WHITE][PIECE_EMPTY] & pos->pieces[SIDE_BLACK][PIECE_EMPTY]);\
\
if (type == MG_CHECKS) {\
allowed &= pawn_attacks_##opp_side(pos->pieces[other_side(side_enum)][PIECE_KING]);\
@@ -127,7 +111,7 @@ static void all_pseudolegal_pawn_attacks_##side(struct pos const* restrict pos,\
size_t* restrict out_count,\
struct move out[restrict static MOVE_MAX])\
{\
Bb64 const their_occ = pos->occupied[other_side(side_enum)];\
Bb64 const their_occ = ~pos->pieces[other_side(side_enum)][PIECE_EMPTY];\
\
if (type == MG_CHECKS) {\
allowed &= pawn_attacks_##opp_side(pos->pieces[other_side(side_enum)][PIECE_KING]);\
@@ -177,7 +161,7 @@ static void all_pseudolegal_moves(struct pos const* restrict pos,
Bb64 const their_threats = all_threats_from_side(pos, them);
Bb64 const their_occ = pos->occupied[them];
Bb64 const their_occ = ~pos->pieces[them][PIECE_EMPTY];
Bb64 allowed;
if (type == MG_CAPTURES) {
@@ -243,7 +227,7 @@ static void all_pseudolegal_moves(struct pos const* restrict pos,
/* castling */
if (!chk && type != MG_CAPTURES) {
bool can_castle_kingside, can_castle_queenside;
Bb64 const blocked = pos->occupied[SIDE_WHITE] | pos->occupied[SIDE_BLACK] | their_threats;
Bb64 const blocked = ~(pos->pieces[SIDE_WHITE][PIECE_EMPTY] & pos->pieces[SIDE_BLACK][PIECE_EMPTY]) | their_threats;
if (us == SIDE_WHITE) {
can_castle_kingside = !(blocked & (SQMASK_F1 | SQMASK_G1))
&& (pos->pieces[us][PIECE_ROOK] & SQMASK_H1)

24
engine-types.h
View File

@@ -195,6 +195,7 @@ static char const* side_str[SIDE_COUNT] = {
/* https://en.wikipedia.org/wiki/X_macro */
/* enum value white char white unicode black char black unicode */
#define PIECES \
X(PIECE_EMPTY, 0.0f, ' ', ' ', ' ', ' ') \
X(PIECE_PAWN, 1.0f, 'P', 0x2659, 'p', 0x265F) \
X(PIECE_KNIGHT, 3.1f, 'N', 0x2658, 'n', 0x265E) \
X(PIECE_BISHOP, 3.2f, 'B', 0x2657, 'b', 0x265D) \
@@ -207,8 +208,8 @@ typedef enum piece : uint8_t {
#define X(e, v, wc, wu, bc, bu) e,
PIECES
PIECE_COUNT,
PIECE_BEGIN = 0,
PIECE_POISONED, /* used as default undefined value in debug builds */
PIECE_BEGIN = PIECE_PAWN,
PIECE_POISONED, /* used as undefined value in debug builds */
#undef X
} Piece8;
@@ -273,6 +274,25 @@ struct move {
#define APPEAL_MAX UINT8_MAX
uint8_t appeal;
};
/*
* Move32 layout:
* f (from piece): 3 bits
* F (from square): 6 bits
* t (to piece): 3 bits
* T (to square): 6 bits
* p (promotion): ? bits (likely 3)
* [x,x,x,x,x,x,x,x,x,x,x,p,p,p,T,T,T,T,T,T,t,t,t,F,F,F,F,F,F,f,f,f]
* */
typedef uint32_t Move32;
#define MOVE_FROM_PIECE(m) (m & 0b000000000000000000111)
#define MOVE_FROM_SQUARE(m) (m & 0b000000000000111111000)
#define MOVE_TO_PIECE(m) (m & 0b000000000111000000000)
#define MOVE_TO_SQUARE(m) (m & 0b000111111000000000000)
#define MOVE_PROMOTION(m) (m & 0b111000000000000000000)
_Static_assert(sizeof(struct move) == 4,
"this static assuming is here to check when sizeof(move) changes");

23
engine.h
View File

@@ -36,14 +36,17 @@ static void move_compute_appeal(struct move* restrict m,
Side8 them = other_side(us);
Piece8 const atk = mailbox[m->from];
uint8_t n = 1;
if (MASK_FROM_SQ(m->to) & pos->occupied[them]) {
uint8_t n = 0;
if ((MASK_FROM_SQ(m->to) & pos->pieces[them][PIECE_EMPTY]) == 0) {
n += (uint8_t)piece_value[mailbox[m->to]];
}
uint8_t mmv_lva_bonus = (uint8_t)(16.0f*(float)n - piece_value[atk]);
m->appeal = mmv_lva_bonus;
/* TODO: remove branch */
if (n) {
m->appeal = (uint8_t)(16.0f*(float)n - piece_value[atk]);
} else {
m->appeal = 0;
}
}
static float board_score_heuristic(struct pos const* pos)
@@ -52,9 +55,8 @@ static float board_score_heuristic(struct pos const* pos)
eventually flipping the sign based on `pos` */
float score = 0.0f;
Bb64 const occw = pos->occupied[SIDE_WHITE];
Bb64 const occb = pos->occupied[SIDE_BLACK];
Bb64 const occall = occw | occb;
Bb64 const occw = ~pos->pieces[SIDE_WHITE][PIECE_EMPTY];
Bb64 const occb = ~pos->pieces[SIDE_BLACK][PIECE_EMPTY];
enum game_progress const gp = endgameness(pos);
@@ -172,8 +174,9 @@ float quiesce(struct pos const* pos,
all_pseudolegal_moves(pos, MG_CAPTURES, us, &move_count, moves);
if (move_count == 0) {
return -(SCORE_CHECKMATE + (float)depth);
return score;
}
for (size_t i = 0; i < move_count; ++i) {
move_compute_appeal(&moves[i], pos, us, mailbox);
}
@@ -181,7 +184,7 @@ float quiesce(struct pos const* pos,
while (move_count) {
struct move m = moves_linear_search(moves, &move_count);
assuming((pos->occupied[them] | pos->ep_targets) & MASK_FROM_SQ(m.to));
assuming((~pos->pieces[them][PIECE_EMPTY] | pos->ep_targets) & MASK_FROM_SQ(m.to));
struct pos poscpy = *pos;

4
sys.h
View File

@@ -20,8 +20,8 @@ static size_t g_buf_len = 0;
static void* sys_mmap_anon_shared(size_t size, int, int)
{
/* FIXME: this program relies on very few memory allocations, a simple bump
* allocator works for now, but will cause memory leaks in the future */
/* FIXME: this program relies on very few memory allocations, a simple bump
* allocator works for now, but will cause memory leaks in the future */
size = (size + 7ULL) & ~7ULL;
if (g_buf_len + size > sizeof g_buf) {

3
tests.c
View File

@@ -440,9 +440,6 @@ int main()
//board_print_fen(b->pos, stdout);
board_print(&b->pos, NULL, stdout, print_threats);
struct move moves[MOVE_MAX];
size_t move_count;
for (int turn = 0; turn < 200; ++turn) {
/*
move_count = 0;