/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
Bitboard RookPseudoAttacks[64];
Bitboard QueenPseudoAttacks[64];
+uint8_t BitCount8Bit[256];
+
////
//// Local definitions
#if defined(IS_64BIT) && !defined(USE_BSFQ)
-static const int BitTable[64] = {
+static CACHE_LINE_ALIGNMENT
+const int BitTable[64] = {
0, 1, 2, 7, 3, 13, 8, 19, 4, 25, 14, 28, 9, 34, 20, 40, 5, 17, 26, 38, 15,
46, 29, 48, 10, 31, 35, 54, 21, 50, 41, 57, 63, 6, 12, 18, 24, 27, 33, 39,
16, 37, 45, 47, 30, 53, 49, 56, 62, 11, 23, 32, 36, 44, 52, 55, 61, 22, 43,
#elif !defined(USE_BSFQ)
-static const int BitTable[64] = {
+static CACHE_LINE_ALIGNMENT
+const int BitTable[64] = {
63, 30, 3, 32, 25, 41, 22, 33, 15, 50, 42, 13, 11, 53, 19, 34, 61, 29, 2,
51, 21, 43, 45, 10, 18, 47, 1, 54, 9, 57, 0, 35, 62, 31, 40, 4, 49, 5, 52,
26, 60, 6, 23, 44, 46, 27, 56, 16, 7, 39, 48, 24, 59, 14, 12, 55, 38, 28,
Bitboard b;
struct {
+#if defined (BIGENDIAN)
+ uint32_t h;
+ uint32_t l;
+#else
uint32_t l;
uint32_t h;
+#endif
} dw;
};
-// WARNING: Needs -fno-strict-aliasing compiler option
Square pop_1st_bit(Bitboard* bb) {
- b_union u;
- uint32_t b;
-
- u.b = *bb;
-
- if (u.dw.l)
- {
- b = u.dw.l;
- *((uint32_t*)bb) = b & (b - 1);
- b ^= (b - 1);
- }
- else
- {
- b = u.dw.h;
- *((uint32_t*)bb+1) = b & (b - 1); // Little endian only?
- b = ~(b ^ (b - 1));
- }
- return Square(BitTable[(b * 0x783a9b23) >> 26]);
+ b_union u;
+ Square ret;
+
+ u.b = *bb;
+
+ if (u.dw.l)
+ {
+ ret = Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
+ u.dw.l &= (u.dw.l - 1);
+ *bb = u.b;
+ return ret;
+ }
+ ret = Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
+ u.dw.h &= (u.dw.h - 1);
+ *bb = u.b;
+ return ret;
}
#endif
+// Optimized bitScanReverse32() implementation by Pascal Georges. Note
+// that first bit is 1, this allow to differentiate between 0 and 1.
+static CACHE_LINE_ALIGNMENT
+const char MsbTable[256] = {
+ 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5,
+ 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+ 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+ 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
+ 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
+};
+
+int bitScanReverse32(uint32_t b)
+{
+ int result = 0;
+
+ if (b > 0xFFFF)
+ {
+ b >>= 16;
+ result += 16;
+ }
+ if (b > 0xFF)
+ {
+ b >>= 8;
+ result += 8;
+ }
+ return result + MsbTable[b];
+}
+
namespace {
// All functions below are used to precompute various bitboards during
in_front_bb(c, s) & this_and_neighboring_files_bb(s);
OutpostMask[c][s] = in_front_bb(c, s) & neighboring_files_bb(s);
}
+
+ for (Bitboard b = 0ULL; b < 256ULL; b++)
+ BitCount8Bit[b] = (uint8_t)count_1s(b);
}