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Code Issues Releases Wiki Activity

Small pick_magic() touches

Browse source 
No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2011-06-08 07:04:13 +01:00
parent d632e77058
commit 3dfff5bdae
1 changed files with 18 additions and 25 deletions
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43
src/bitboard.cpp
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@ -65,8 +65,8 @@ namespace {
Bitboard RAttacksTable[0x19000];
Bitboard BAttacksTable[0x1480];
void do_magics(Bitboard magic[], Bitboard* attack[], Bitboard attTabl[],
Bitboard mask[], int shift[], Square deltas[]);
void init_sliding_attacks(Bitboard magic[], Bitboard* attack[], Bitboard attTable[],
Bitboard mask[], int shift[], Square delta[]);
}
@ -226,8 +226,8 @@ void init_bitboards() {
Square RDeltas[] = { DELTA_N, DELTA_E, DELTA_S, DELTA_W };
Square BDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW };
do_magics(BMult, BAttacks, BAttacksTable, BMask, BShift, BDeltas);
do_magics(RMult, RAttacks, RAttacksTable, RMask, RShift, RDeltas);
init_sliding_attacks(BMult, BAttacks, BAttacksTable, BMask, BShift, BDeltas);
init_sliding_attacks(RMult, RAttacks, RAttacksTable, RMask, RShift, RDeltas);
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
@ -293,10 +293,6 @@ namespace {
Bitboard pick_magic(Bitboard mask, RKISS& rk, int booster) {
Bitboard magic;
int lsb;
if (!Is64)
lsb = first_1(mask);
// Advance PRNG state of a quantity known to be the optimal to
// quickly retrieve all the magics.
@ -308,41 +304,40 @@ namespace {
magic = rk.rand<Bitboard>() & rk.rand<Bitboard>();
magic &= Is64 ? rk.rand<Bitboard>() : (rk.rand<Bitboard>() | rk.rand<Bitboard>());
if ( BitCount8Bit[(mask * magic) >> 56] >= 6
&& (Is64 || BitCount8Bit[(lsb * magic) >> 56]))
if (BitCount8Bit[(mask * magic) >> 56] >= 6)
return magic;
}
}
void do_magics(Bitboard magic[], Bitboard* attack[], Bitboard attTabl[],
Bitboard mask[], int shift[], Square deltas[]) {
const int MagicBoosters32[] = { 43, 53, 76, 17, 51, 65, 55, 23 };
const int MagicBoosters64[] = { 26, 21, 21, 32, 31, 9, 5, 11 };
void init_sliding_attacks(Bitboard magic[], Bitboard* attack[], Bitboard attTable[],
Bitboard mask[], int shift[], Square delta[]) {
const int MagicBoosters[][8] = { { 55, 11, 17, 2, 39, 3, 31, 44 },
{ 26, 21, 21, 32, 31, 9, 5, 11 } };
RKISS rk;
Bitboard occupancy[4096], proofs[4096], excluded;
Bitboard occupancy[4096], reference[4096], excluded;
int key, maxKey, index, booster, offset = 0;
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
excluded = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s));
attack[s] = &attTabl[offset];
mask[s] = sliding_attacks(s, EmptyBoardBB, deltas, excluded);
attack[s] = &attTable[offset];
mask[s] = sliding_attacks(s, EmptyBoardBB, delta, excluded);
shift[s] = (CpuIs64Bit ? 64 : 32) - count_1s<CNT64>(mask[s]);
maxKey = 1 << count_1s<CNT32>(mask[s]);
booster = CpuIs64Bit ? MagicBoosters64[square_rank(s)] : MagicBoosters32[square_rank(s)];
offset += maxKey;
booster = MagicBoosters[CpuIs64Bit][square_rank(s)];
// First compute occupancy and attacks for square 's'
for (key = 0; key < maxKey; key++)
{
occupancy[key] = submask(mask[s], key);
proofs[key] = sliding_attacks(s, occupancy[key], deltas, EmptyBoardBB);
reference[key] = sliding_attacks(s, occupancy[key], delta, EmptyBoardBB);
}
// Then find a possible magic and corresponding attacks
// Then find a possible magic and the corresponding attacks
do {
magic[s] = pick_magic<CpuIs64Bit>(mask[s], rk, booster);
memset(attack[s], 0, maxKey * sizeof(Bitboard));
@ -353,14 +348,12 @@ namespace {
: unsigned(occupancy[key] * magic[s] ^ (occupancy[key] >> 32) * (magic[s] >> 32)) >> shift[s];
if (!attack[s][index])
attack[s][index] = proofs[key];
attack[s][index] = reference[key];
else if (attack[s][index] != proofs[key])
else if (attack[s][index] != reference[key])
break;
}
} while (key != maxKey);
offset += maxKey;
}
}
}