1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
|
/*++
Copyright (c) Scott Gasch
Module Name:
poshash.c
Abstract:
A hash table of information about positions.
Author:
Scott Gasch (SGasch) 11 Nov 2006
Revision History:
--*/
#include "chess.h"
#define NUM_POSITION_HASH_ENTRIES (1048576) // 16Mb
POSITION_HASH_ENTRY g_PositionHash[NUM_POSITION_HASH_ENTRIES];
#ifdef MP
#define NUM_POSITION_HASH_LOCKS (512)
volatile static ULONG g_uPositionHashLocks[NUM_POSITION_HASH_LOCKS];
#define POSITION_HASH_IS_LOCKED(x) ((g_uPositionHashLocks[(x)]) != 0)
#define LOCK_POSITION_HASH(x) \
AcquireSpinLock(&(g_uPositionHashLocks[(x)])); \
ASSERT(POSITION_HASH_IS_LOCKED(x))
#define UNLOCK_POSITION_HASH(x) \
ASSERT(POSITION_HASH_IS_LOCKED(x)); \
ReleaseSpinLock(&(g_uPositionHashLocks[(x)]))
#else
#define POSITION_HASH_IS_LOCKED(x)
#define LOCK_HASH(x)
#define UNLOCK_HASH(x)
#endif
void
InitializePositionHashSystem(void)
{
memset(&g_PositionHash, 0, sizeof(g_PositionHash));
#ifdef MP
memset(&g_uPositionHashLocks, 0, sizeof(g_uPositionHashLocks));
#endif
}
void
CleanupPositionHashSystem(void)
{
; // do nothing
}
static INLINE UINT64 PositionToSignatureIgnoringMove(POSITION *pos)
{
return((pos->u64NonPawnSig ^ pos->u64PawnSig) >> 1);
}
// Note: sig must be pre-shifted to ignore the side-to-move bit.
static INLINE ULONG PositionSigToHashPosition(UINT64 u64Sig)
{
ULONG u = (ULONG)u64Sig;
u &= (NUM_POSITION_HASH_ENTRIES - 1);
ASSERT(u < NUM_POSITION_HASH_ENTRIES);
return u;
}
#ifdef MP
static INLINE ULONG HashPositionToLockNumber(ULONG u)
{
u &= (NUM_POSITION_HASH_LOCKS - 1);
ASSERT(u < NUM_POSITION_HASH_LOCKS);
return u;
}
#endif
void
StoreEnprisePiece(POSITION *pos, COOR cSquare)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
PIECE p = pos->rgSquare[cSquare].pPiece;
ULONG uColor = GET_COLOR(p);
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
ASSERT(p && IS_VALID_PIECE(p));
ASSERT(!IS_PAWN(p));
ASSERT(CAN_FIT_IN_UCHAR(cSquare));
ASSERT(IS_ON_BOARD(cSquare));
pHash->cEnprise[uColor] = (UCHAR)cSquare;
ASSERT(pHash->uEnpriseCount[uColor] < 16);
pHash->uEnpriseCount[uColor] += 1;
if (pHash->u64Sig != u64Sig)
{
pHash->u64Sig = u64Sig;
pHash->uEnpriseCount[uColor] = 1;
pHash->cTrapped[uColor] = ILLEGAL_COOR;
uColor = FLIP(uColor);
pHash->cEnprise[uColor] = ILLEGAL_COOR;
pHash->cTrapped[uColor] = ILLEGAL_COOR;
pHash->uEnpriseCount[uColor] = 0;
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
}
void
StoreTrappedPiece(POSITION *pos, COOR cSquare)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
PIECE p = pos->rgSquare[cSquare].pPiece;
ULONG uColor = GET_COLOR(p);
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
ASSERT(p && IS_VALID_PIECE(p));
ASSERT(!IS_PAWN(p));
ASSERT(CAN_FIT_IN_UCHAR(cSquare));
ASSERT(IS_ON_BOARD(cSquare));
pHash->cTrapped[uColor] = cSquare;
if (pHash->u64Sig != u64Sig)
{
pHash->u64Sig = u64Sig;
pHash->cEnprise[uColor] = ILLEGAL_COOR;
pHash->uEnpriseCount[uColor] = 0;
uColor = FLIP(uColor);
pHash->cEnprise[uColor] = ILLEGAL_COOR;
pHash->cTrapped[uColor] = ILLEGAL_COOR;
pHash->uEnpriseCount[uColor] = 0;
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
}
COOR
GetEnprisePiece(POSITION *pos, ULONG uSide)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
COOR c = ILLEGAL_COOR;
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
if (pHash->u64Sig == u64Sig)
{
c = pHash->cEnprise[uSide];
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
return c;
}
COOR
GetTrappedPiece(POSITION *pos, ULONG uSide)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
COOR c = ILLEGAL_COOR;
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
if (pHash->u64Sig == u64Sig)
{
c = pHash->cTrapped[uSide];
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
return c;
}
FLAG
SideCanStandPat(POSITION *pos, ULONG uSide)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
FLAG fStand = TRUE;
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
if (pHash->u64Sig == u64Sig)
{
fStand = ((pHash->cTrapped[uSide] == ILLEGAL_COOR) &&
(pHash->uEnpriseCount[uSide] < 2));
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
return fStand;
}
ULONG
ValueOfMaterialInTroubleDespiteMove(POSITION *pos, ULONG uSide)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
ULONG u = 0;
COOR c;
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
if (pHash->u64Sig == u64Sig)
{
if (pHash->uEnpriseCount[uSide] > 1)
{
c = pHash->cEnprise[uSide];
ASSERT(IS_ON_BOARD(c));
u = PIECE_VALUE(pos->rgSquare[c].pPiece);
ASSERT(u);
}
c = pHash->cTrapped[uSide];
if (IS_ON_BOARD(c))
{
u = MAXU(u, PIECE_VALUE(pos->rgSquare[c].pPiece));
ASSERT(u);
}
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
return u;
}
ULONG
ValueOfMaterialInTroubleAfterNull(POSITION *pos, ULONG uSide)
{
UINT64 u64Sig = PositionToSignatureIgnoringMove(pos);
ULONG uEntry = PositionSigToHashPosition(u64Sig);
POSITION_HASH_ENTRY *pHash = &(g_PositionHash[uEntry]);
ULONG u = 0;
COOR c;
#ifdef MP
ULONG uLock = HashPositionToLockNumber(uEntry);
LOCK_POSITION_HASH(uLock);
#endif
if (pHash->u64Sig == u64Sig)
{
if (pHash->uEnpriseCount[uSide])
{
c = pHash->cEnprise[uSide];
ASSERT(IS_ON_BOARD(c));
u += PIECE_VALUE(pos->rgSquare[c].pPiece);
ASSERT(u);
}
c = pHash->cTrapped[uSide];
if (IS_ON_BOARD(c))
{
u = MAXU(PIECE_VALUE(pos->rgSquare[c].pPiece), u);
ASSERT(u);
}
}
#ifdef MP
UNLOCK_POSITION_HASH(uLock);
#endif
return u;
}
|
