HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-20 09:06:45 +08:00
Code Issues Packages Projects Releases Wiki Activity

Retire one implementation of pop_lsb()

Browse Source 
We have two implementations that are equivalent,
so retire one.

Plus usual tidy up of comments and code reshuffle.

No functional change.
This commit is contained in:
Marco Costalba
2015-01-03 16:39:17 +01:00
parent a6e292034a
commit 3fda064a66
6 changed files with 130 additions and 131 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
src/bitboard.cpp
View File

@@ -24,15 +24,17 @@
#include "bitcount.h"
#include "misc.h"
Bitboard RookMasks[SQUARE_NB];
Bitboard RookMagics[SQUARE_NB];
Bitboard* RookAttacks[SQUARE_NB];
unsigned RookShifts[SQUARE_NB];
int SquareDistance[SQUARE_NB][SQUARE_NB];
Bitboard BishopMasks[SQUARE_NB];
Bitboard BishopMagics[SQUARE_NB];
Bitboard RookMasks [SQUARE_NB];
Bitboard RookMagics [SQUARE_NB];
Bitboard* RookAttacks[SQUARE_NB];
unsigned RookShifts [SQUARE_NB];
Bitboard BishopMasks [SQUARE_NB];
Bitboard BishopMagics [SQUARE_NB];
Bitboard* BishopAttacks[SQUARE_NB];
unsigned BishopShifts[SQUARE_NB];
unsigned BishopShifts [SQUARE_NB];
Bitboard SquareBB[SQUARE_NB];
Bitboard FileBB[FILE_NB];
@@ -42,51 +44,44 @@ Bitboard InFrontBB[COLOR_NB][RANK_NB];
Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
Bitboard LineBB[SQUARE_NB][SQUARE_NB];
Bitboard DistanceRingsBB[SQUARE_NB][8];
Bitboard DistanceRingBB[SQUARE_NB][8];
Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
int SquareDistance[SQUARE_NB][SQUARE_NB];
namespace {
// De Bruijn sequences. See chessprogramming.wikispaces.com/BitScan
const uint64_t DeBruijn_64 = 0x3F79D71B4CB0A89ULL;
const uint32_t DeBruijn_32 = 0x783A9B23;
const uint64_t DeBruijn64 = 0x3F79D71B4CB0A89ULL;
const uint32_t DeBruijn32 = 0x783A9B23;
int MS1BTable[256];
Square BSFTable[SQUARE_NB];
Bitboard RookTable[0x19000]; // Storage space for rook attacks
Bitboard BishopTable[0x1480]; // Storage space for bishop attacks
int MS1BTable[256]; // To implement software msb()
Square BSFTable[SQUARE_NB]; // To implement software bitscan
Bitboard RookTable[0x19000]; // To store rook attacks
Bitboard BishopTable[0x1480]; // To store bishop attacks
typedef unsigned (Fn)(Square, Bitboard);
void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
Bitboard masks[], unsigned shifts[], Square deltas[], Fn index);
FORCE_INLINE unsigned bsf_index(Bitboard b) {
// bsf_index() returns the index into BSFTable[] to look up the bitscan. Uses
// Matt Taylor's folding for 32 bit case, extended to 64 bit by Kim Walisch.
// Matt Taylor's folding for 32 bit systems, extended to 64 bits by Kim Walisch
b ^= (b - 1);
return Is64Bit ? (b * DeBruijn_64) >> 58
: ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn_32) >> 26;
FORCE_INLINE unsigned bsf_index(Bitboard b) {
b ^= b - 1;
return Is64Bit ? (b * DeBruijn64) >> 58
: ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn32) >> 26;
}
}
/// lsb()/msb() finds the least/most significant bit in a non-zero bitboard.
/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard.
#ifndef USE_BSFQ
Square lsb(Bitboard b) { return BSFTable[bsf_index(b)]; }
/// Software fall-back of lsb() and msb() for CPU lacking hardware support
Square pop_lsb(Bitboard* b) {
Bitboard bb = *b;
*b = bb & (bb - 1);
return BSFTable[bsf_index(bb)];
Square lsb(Bitboard b) {
return BSFTable[bsf_index(b)];
}
Square msb(Bitboard b) {
@@ -120,8 +115,8 @@ Square msb(Bitboard b) {
#endif // ifndef USE_BSFQ
/// Bitboards::pretty() returns an ASCII representation of a bitboard to be
/// printed to standard output. This is sometimes useful for debugging.
/// Bitboards::pretty() returns an ASCII representation of a bitboard suitable
/// to be printed to standard output. Useful for debugging.
const std::string Bitboards::pretty(Bitboard b) {
@@ -178,7 +173,7 @@ void Bitboards::init() {
if (s1 != s2)
{
SquareDistance[s1][s2] = std::max(distance<File>(s1, s2), distance<Rank>(s1, s2));
DistanceRingsBB[s1][SquareDistance[s1][s2] - 1] |= s2;
DistanceRingBB[s1][SquareDistance[s1][s2] - 1] |= s2;
}
int steps[][9] = { {}, { 7, 9 }, { 17, 15, 10, 6, -6, -10, -15, -17 },