diff options
Diffstat (limited to 'src/see.c')
| -rwxr-xr-x | src/see.c | 175 |
1 files changed, 25 insertions, 150 deletions
@@ -28,144 +28,17 @@ Revision History: pList->data[pList->uCount].uVal = (v); \ pList->uCount++; -void CDECL -SlowGetAttacks(IN OUT SEE_LIST *pList, - IN POSITION *pos, - IN COOR cSquare, - IN ULONG uSide) -/*++ - -Routine description: - - SlowGetAttacks is the C version of GetAttacks; it should be - identical to the GetAttacks code in x86.asm. The job of the - function is, given a position, square and side, to populate the - SEE_LIST with the locations and types of enemy pieces attacking - the square. - -Parameters: - - SEE_LIST *pList : list to populate - POSITION *pos : the board - COOR cSquare : square in question - ULONG uSide : side we are looking for attacks from - -Return value: - - void - ---*/ -{ - register ULONG x; - PIECE p; - COOR c; - int iIndex; - COOR cBlockIndex; - int iDelta; - static PIECE pPawn[2] = { BLACK_PAWN, WHITE_PAWN }; - static int iSeeDelta[2] = { -17, +15 }; - -#ifdef DEBUG - ASSERT(IS_ON_BOARD(cSquare)); - ASSERT(IS_VALID_COLOR(uSide)); - VerifyPositionConsistency(pos, FALSE); -#endif - pList->uCount = 0; - - // - // Check for pawns attacking cSquare - // - c = cSquare + (iSeeDelta[uSide]); - if (IS_ON_BOARD(c)) - { - p = pos->rgSquare[c].pPiece; - if (p == pPawn[uSide]) - { - // - // N.B. Don't use ADD_ATTACKER here because we know we're - // at element zero. - // - pList->data[0].pPiece = p; - pList->data[0].cLoc = c; - pList->data[0].uVal = VALUE_PAWN; - pList->uCount = 1; - } - } - - c += 2; - if (IS_ON_BOARD(c)) - { - p = pos->rgSquare[c].pPiece; - if (p == pPawn[uSide]) - { - ADD_ATTACKER(p, c, VALUE_PAWN); - } - } - - // - // Check for pieces attacking cSquare - // - for (x = pos->uNonPawnCount[uSide][0] - 1; - x != (ULONG)-1; - x--) - { - c = pos->cNonPawns[uSide][x]; - ASSERT(IS_ON_BOARD(c)); - - p = pos->rgSquare[c].pPiece; - ASSERT(p && !IS_PAWN(p)); - ASSERT(GET_COLOR(p) == uSide); - - iIndex = (int)c - (int)cSquare; - if (0 == (CHECK_VECTOR_WITH_INDEX(iIndex, GET_COLOR(p)) & - (1 << PIECE_TYPE(p)))) - { - continue; - } - - if (IS_KNIGHT_OR_KING(p)) - { - ASSERT(IS_KNIGHT(p) || IS_KING(p)); - ADD_ATTACKER(p, c, PIECE_VALUE(p)); - continue; - } - - // - // Check to see if there is a piece in the path from cSquare - // to c that blocks the attack. - // - iDelta = NEG_DELTA_WITH_INDEX(iIndex); - ASSERT(iDelta == -1 * CHECK_DELTA_WITH_INDEX(iIndex)); - ASSERT(iDelta != 0); - for (cBlockIndex = cSquare + iDelta; - cBlockIndex != c; - cBlockIndex += iDelta) - { - if (!IS_EMPTY(pos->rgSquare[cBlockIndex].pPiece)) - { - goto done; - } - } - - // - // Nothing in the way. - // - ADD_ATTACKER(p, c, PIECE_VALUE(p)); - - done: - ; - } -} - // -// board_representation/MIGRATION.md section 3: bbPieces-backed -// "who attacks square X" primitive, and a GetAttacks PoC built on -// it. Not wired into the GetAttacks macro yet -- see MIGRATION.md -// section 6 for the eventual toggle. Uses chess.h's FastFirstBit/ -// FastLastBit (static inline bsf/bsr wrappers) rather than the real -// out-of-line FirstBit/LastBit -- worth avoiding call overhead in a -// per-move-generated, per-node hot path like this one. +// board_representation/MIGRATION.md sections 3/6/7: bbPieces-backed +// "who attacks square X" primitive. _GetAttacksBB below is now the +// only GetAttacks implementation -- the old mailbox SlowGetAttacks/ +// asm GetAttacks were retired 2026-09-06 once all of section 7's +// retirement criteria (correctness sweep, isolated + whole-engine +// benchmarks, match_play.py gate) cleared. Uses chess.h's +// FastFirstBit/FastLastBit (static inline bsf/bsr wrappers) rather +// than the real out-of-line FirstBit/LastBit -- worth avoiding call +// overhead in a per-move-generated, per-node hot path like this one. // // (This file used to have its own static _BuildOccupiedBB here, // byte-for-byte identical to generate.c's _BuildFullOccupiedBB -- @@ -191,8 +64,8 @@ Routine description: Return a bitboard of every uSide knight/bishop/rook/queen/king that attacks cSquare in the current position, blockers included. - Pawns are deliberately excluded -- see GetAttacksBB, which handles - them the same 2-square-delta way SlowGetAttacks always has (already + Pawns are deliberately excluded -- see _GetAttacksBB, which handles + them the same 2-square-delta way the old mailbox code did (already O(1), nothing to improve). Knights and the king are pure O(1) table/delta lookups (no @@ -319,19 +192,21 @@ _GetAttacksBB(IN OUT SEE_LIST *pList, Routine description: - PROOF OF CONCEPT -- not called from anywhere yet, and not a - replacement for GetAttacks/SlowGetAttacks until section 4/5/6 of - board_representation/MIGRATION.md (correctness sweep, benchmark, - toggle) are done. Reproduces SlowGetAttacks's exact semantics - (same deliberately-approximate no-pin/no-en-passant contract) via - _WhoAttacksSquareBB instead of the O(non-pawn-piece-count) mailbox - walk -- pawns handled identically to SlowGetAttacks (2-square - delta, unchanged, already O(1)). + The only GetAttacks implementation as of 2026-09-06 -- the old + mailbox SlowGetAttacks/asm GetAttacks retired once all of + board_representation/MIGRATION.md section 7's retirement criteria + cleared (correctness sweep, isolated + whole-engine benchmarks, + match_play.py gate). Reproduces the old mailbox code's exact + semantics (same deliberately-approximate no-pin/no-en-passant + contract) via _WhoAttacksSquareBB instead of an + O(non-pawn-piece-count) mailbox walk -- pawns handled the same way + the mailbox version always did (2-square delta, unchanged, already + O(1)). - Attacker order is not guaranteed to match SlowGetAttacks -- see() - sorts/heaps the list immediately after GetAttacks returns, so only - the *set* of attackers needs to match, not the sequence - (board_representation/MIGRATION.md section 4). + Attacker order is not guaranteed to match the old mailbox + implementation -- see() sorts/heaps the list immediately after + GetAttacks returns, so only the *set* of attackers needs to match, + not the sequence (board_representation/MIGRATION.md section 4). Parameters: |