From 6d5526c41d7279be959b90fa6bb7109ca2ac7676 Mon Sep 17 00:00:00 2001
From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Wed, 11 Apr 2018 19:37:00 +0200
Subject: [PATCH] Implement move exclusion

A 64KB moveMap[] is added to keep track of which moves are excluded in the
root. It is indexed directly by the lowest 16 bits of the move code,
(the from- and to-square), and can be almost entirely used, as the board
measures 121 squares, an the 'shadow' board (another 121 squares) can be used
both as from- and to-square as well. So that in theory 242*242 moves can
be encoded.
---
 dropper.c |   24 ++++++++++++++++++------
 1 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/dropper.c b/dropper.c
index e967a55..07fe17d 100644
--- a/dropper.c
+++ b/dropper.c
@@ -888,6 +888,7 @@ Dump (char *s)
 #define attacks (rawAttacks + 23)
 static int attackKey, rawAttacks[13*22];
 int depthLimit = MAXPLY;
+char moveMap[1<<16]; // excluded root moves
 
 int
 MoveGen (int stm, MoveStack *m, int castle)
@@ -1435,6 +1436,8 @@ Search (int stm, int alpha, int beta, StackFrame *ff, int depth, int reduction,
 		}
 	    }
 
+	    if(ply == 0 && moveMap[moveStack[curMove] & 0xFFFF]) continue; // excluded root move
+
 	    // make move
 	    if(MakeMove(&f, moveStack[curMove])) { // aborts if fails to evade existing check
 
@@ -1816,6 +1819,12 @@ void PrintResult(int stm, int score)
   else printf("0-1\n");
 }
 
+void
+MapClear (int n)
+{
+  int i; for(i=0; i<0x10000; i++) moveMap[i] = n;
+}
+
 int ponderMove;
 char inBuf[800];
 
@@ -1879,7 +1888,7 @@ printf("# command: %s\n", inBuf);
       return 1;
     }
     if(!strcmp(command, "protover")){
-      printf("feature ping=1 setboard=1 colors=0 usermove=1 memory=1 debug=1 reuse=0 sigint=0 sigterm=0 myname=\"CrazyWa " VERSION "\"\n");
+      printf("feature ping=1 setboard=1 colors=0 usermove=1 memory=1 debug=1 reuse=0 sigint=0 sigterm=0 exclude=1 myname=\"CrazyWa " VERSION "\"\n");
       printf("feature variants=\"crazyhouse,shogi,minishogi,judkinshogi,torishogi,euroshogi,crazywa,kyotoshogi,"
 				"5x5+4_shogi,5x5+5_shogi,6x6+6_shogi,7x7+6_shogi,11x17+16_chu\"\n");
       printf("feature option=\"Resign -check 0\"\n");           // example of an engine-defined option
@@ -1892,13 +1901,16 @@ printf("# command: %s\n", inBuf);
     if(!strcmp(command, "memory"))  { if(SetMemorySize(atoi(inBuf+7))) printf("tellusererror Not enough memory\n"), exit(-1); return 1; }
     if(!strcmp(command, "ping"))    { printf("pong%s", inBuf+4); return 1; }
 //  if(!strcmp(command, ""))        { sscanf(inBuf, " %d", &); return 1; }
-    if(!strcmp(command, "new"))     { engineSide = BLACK; stm = WHITE; maxDepth = MAXPLY-2; randomize = OFF; moveNr = 0; ranKey = GetTickCount() | 0x1001; return 1; }
+    if(!strcmp(command, "new"))     { engineSide = BLACK; stm = WHITE; maxDepth = MAXPLY-2; randomize = OFF;
+				      moveNr = 0; ranKey = GetTickCount() | 0x1001; MapClear(0); return 1; }
     if(!strcmp(command, "variant")) { GameInit(inBuf + 8); Setup(startPos); return 1; }
-    if(!strcmp(command, "setboard")){ engineSide = NONE;  stm = Setup(inBuf+9); return 1; }
-    if(!strcmp(command, "undo"))    { TakeBack(1); return 1; }
-    if(!strcmp(command, "remove"))  { TakeBack(2); return 1; }
+    if(!strcmp(command, "setboard")){ engineSide = NONE;  stm = Setup(inBuf+9); MapClear(0); return 1; }
+    if(!strcmp(command, "undo"))    { TakeBack(1); MapClear(0); return 1; }
+    if(!strcmp(command, "remove"))  { TakeBack(2); MapClear(0); return 1; }
     if(!strcmp(command, "go"))      { engineSide = stm;  return 1; }
     if(!strcmp(command, "hint"))    { if(ponderMove != INVALID) printf("Hint: %s\n", MoveToText(ponderMove)); return 1; }
+    if(!strcmp(command, "include")) { if(inBuf[9] == 'l') MapClear(0); else moveMap[ParseMove(stm, inBuf+8)] = 0; return 1; }
+    if(!strcmp(command, "exclude")) { if(inBuf[9] == 'l') MapClear(1); else moveMap[ParseMove(stm, inBuf+8)] = 1; return 1; }
     if(!strcmp(command, "book"))    {  return 1; }
     // completely ignored commands:
     if(!strcmp(command, "xboard"))  { return 1; }
@@ -1917,7 +1929,7 @@ printf("# command: %s\n", inBuf);
       if(move == INVALID) printf("Illegal move\n");
       else if(!RootMakeMove(move)) printf("Illegal move\n");
       else {
-        ponderMove = INVALID;
+        ponderMove = INVALID; MapClear(0);
       }
       return 1;
     }
-- 
1.7.0.4