Bitboard InFrontBB[2][8];
Bitboard StepAttacksBB[16][64];
Bitboard BetweenBB[64][64];
+Bitboard DistanceRingsBB[64][8];
Bitboard ForwardBB[2][64];
Bitboard PassedPawnMask[2][64];
Bitboard AttackSpanMask[2][64];
Bitboard masks[], unsigned shifts[], Square deltas[], Fn index);
}
-/// first_1() finds the least significant nonzero bit in a nonzero bitboard.
-/// pop_1st_bit() finds and clears the least significant nonzero bit in a
-/// nonzero bitboard.
+/// lsb()/msb() finds the least/most significant bit in a nonzero bitboard.
+/// pop_lsb() finds and clears the least significant bit in a nonzero bitboard.
-#if defined(IS_64BIT) && !defined(USE_BSFQ)
+#if !defined(USE_BSFQ)
-Square first_1(Bitboard b) {
- return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]);
-}
-
-Square pop_1st_bit(Bitboard* b) {
- Bitboard bb = *b;
- *b &= (*b - 1);
- return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]);
-}
+Square lsb(Bitboard b) {
-#elif !defined(USE_BSFQ)
+ if (Is64Bit)
+ return Square(BSFTable[((b & -b) * 0x218A392CD3D5DBFULL) >> 58]);
-Square first_1(Bitboard b) {
b ^= (b - 1);
uint32_t fold = unsigned(b) ^ unsigned(b >> 32);
return Square(BSFTable[(fold * 0x783A9B23) >> 26]);
}
-Square pop_1st_bit(Bitboard* b) {
+Square pop_lsb(Bitboard* b) {
Bitboard bb = *b;
*b = bb & (bb - 1);
+
+ if (Is64Bit)
+ return Square(BSFTable[((bb & -bb) * 0x218A392CD3D5DBFULL) >> 58]);
+
bb ^= (bb - 1);
uint32_t fold = unsigned(bb) ^ unsigned(bb >> 32);
return Square(BSFTable[(fold * 0x783A9B23) >> 26]);
}
-Square last_1(Bitboard b) {
+Square msb(Bitboard b) {
unsigned b32;
int result = 0;
std::cout << "+---+---+---+---+---+---+---+---+" << '\n';
for (File file = FILE_A; file <= FILE_H; file++)
- std::cout << "| " << (b & make_square(file, rank) ? "X " : " ");
+ std::cout << "| " << (b & (file | rank) ? "X " : " ");
std::cout << "|\n";
}
for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2));
+ for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
+ for (int d = 1; d < 8; d++)
+ for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
+ if (SquareDistance[s1][s2] == d)
+ DistanceRingsBB[s1][d - 1] |= s2;
+
for (int i = 0; i < 64; i++)
if (!Is64Bit) // Matt Taylor's folding trick for 32 bit systems
{