4.4BSD/usr/src/games/chess/move.c
/* move generator hes@log-sv.se 890318
Modified: 890606 NEWMOVE Levels 1-6 for easier debugging */
#include "move.h"
#include "gnuchess.h"
short distdata[64][64];
short taxidata[64][64];
void Initialize_dist() {
register short a,b,d,di;
/* init taxi and dist data */
for(a=0;a<64;a++)
for(b=0;b<64;b++) {
d = abs(column[a]-column[b]);
di = abs(row[a]-row[b]);
taxidata[a][b] = d + di;
distdata[a][b] = (d > di ? d : di);
};
}
#if (NEWMOVE > 1)
struct sqdata posdata[3][8][64][64];
static short direc[8][8] = {
0, 0, 0, 0, 0, 0, 0, 0, /* no_piece = 0 */
-10,-11, -9, 0, 0, 0, 0, 0, /* wpawn = 1 */
-21,-19,-12, -8, 21, 19, 12, 8, /* knight = 2 */
-11, -9, 11, 9, 0, 0, 0, 0, /* bishop = 3 */
-10, -1, 10, 1, 0, 0, 0, 0, /* rook = 4 */
-11, -9,-10, -1, 11, 9, 10, 1, /* queen = 5 */
-11, -9,-10, -1, 11, 9, 10, 1, /* king = 6 */
0, 0, 0, 0, 0, 0, 0, 0};/* no_piece = 7 */
static short dc[3] = {-1,1,0};
static short max_steps [8] = {0,2,1,7,7,7,1,0};
static short unmap[120] = {
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1, 0, 1, 2, 3, 4, 5, 6, 7,-1,
-1, 8, 9,10,11,12,13,14,15,-1,
-1,16,17,18,19,20,21,22,23,-1,
-1,24,25,26,27,28,29,30,31,-1,
-1,32,33,34,35,36,37,38,39,-1,
-1,40,41,42,43,44,45,46,47,-1,
-1,48,49,50,51,52,53,54,55,-1,
-1,56,57,58,59,60,61,62,63,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1};
void Initialize_moves() {
short c,ptyp,po,p0,d,di,s;
struct sqdata *p;
short dest[8][8];
short steps[8];
short sorted[8];
/* init posdata */
for(c=0;c<3;c++)
for(ptyp=0;ptyp<8;ptyp++)
for(po=0;po<64;po++)
for(p0=0;p0<64;p0++) {
posdata[c][ptyp][po][p0].nextpos = po;
posdata[c][ptyp][po][p0].nextdir = po;
};
/* dest is a function of dir and step */
for(c=0;c<2;c++)
for(ptyp=1;ptyp<7;ptyp++)
for(po=21;po<99;po++)
if (unmap[po] >= 0) {
p = posdata[c][ptyp][unmap[po]];
for(d=0;d<8;d++) {
dest[d][0] = unmap[po];
if (dc[c]*direc[ptyp][d] != 0) {
p0=po;
for(s=0;s<max_steps[ptyp];s++) {
p0 = p0 + dc[c]*direc[ptyp][d];
/* break if (off board) or
(pawns move two steps from home square) */
if (unmap[p0] < 0 ||
(ptyp == pawn && s>0 && (d>0 || Stboard[unmap[po]] != ptyp)))
break;
else
dest[d][s] = unmap[p0];
}
}
else s=0;
/* sort dest in number of steps order */
steps[d] = s;
for(di=d;di>0;di--)
if (steps[sorted[di-1]] < s)
sorted[di] = sorted[di-1];
else
break;
sorted[di] = d;
}
/* update posdata, pawns have two threads (capture and no capture) */
p0=unmap[po];
if (ptyp == pawn) {
for(s=0;s<steps[0];s++) {
p[p0].nextpos = dest[0][s];
p0 = dest[0][s];
}
p0=unmap[po];
for(d=1;d<3;d++) {
p[p0].nextdir = dest[d][0];
p0 = dest[d][0];
}
}
else {
p[p0].nextdir = dest[sorted[0]][0];
for(d=0;d<8;d++)
for(s=0;s<steps[sorted[d]];s++) {
p[p0].nextpos = dest[sorted[d]][s];
p0 = dest[sorted[d]][s];
if (d < 7)
p[p0].nextdir = dest[sorted[d+1]][0];
/* else is already initialised */
}
}
#ifdef DEBUG
printf("Ptyp:%d Position:%d\n{",ptyp,unmap[po]);
for(p0=0;p0<63;p0++) printf("%d,",p[p0].nextpos);
printf("%d};\n",p[63].nextpos);
for(p0=0;p0<63;p0++) printf("%d,",p[p0].nextdir);
printf("%d};\n",p[63].nextdir);
#endif DEBUG
}
}
#endif
#if (NEWMOVE > 2)
int SqAtakd(sq,side)
short sq,side;
/*
See if any piece with color 'side' ataks sq. First check pawns
Then Queen, Bishop, Rook and King and last Knight.
*/
{
register short u;
register struct sqdata *p;
p = posdata[1-side][pawn][sq];
u = p[sq].nextdir; /* follow captures thread */
while (u != sq) {
if (board[u] == pawn && color[u] == side) return(true);
u = p[u].nextdir;
}
/* king capture */
if (distance(sq,PieceList[side][0]) == 1) return(true);
/* try a queen bishop capture */
p = posdata[side][bishop][sq];
u = p[sq].nextpos;
while (u != sq) {
if (color[u] == neutral) {
u = p[u].nextpos;
}
else {
if (color[u] == side &&
(board[u] == queen || board[u] == bishop))
return(true);
u = p[u].nextdir;
}
}
/* try a queen rook capture */
p = posdata[side][rook][sq];
u = p[sq].nextpos;
while (u != sq) {
if (color[u] == neutral) {
u = p[u].nextpos;
}
else {
if (color[u] == side &&
(board[u] == queen || board[u] == rook))
return(true);
u = p[u].nextdir;
}
}
/* try a knight capture */
p = posdata[side][knight][sq];
u = p[sq].nextpos;
while (u != sq) {
if (color[u] == neutral) {
u = p[u].nextpos;
}
else {
if (color[u] == side && board[u] == knight) return(true);
u = p[u].nextdir;
}
}
return(false);
}
#endif
#if (NEWMOVE > 3)
BRscan(sq,s,mob)
short sq,*s,*mob;
/*
Find Bishop and Rook mobility, XRAY attacks, and pins. Increment the
hung[] array if a pin is found.
*/
{
register short u,piece,pin;
register struct sqdata *p;
short *Kf;
Kf = Kfield[c1];
*mob = 0;
piece = board[sq];
p = posdata[color[sq]][piece][sq];
u = p[sq].nextpos;
pin = -1; /* start new direction */
while (u != sq) {
*s += Kf[u];
if (color[u] == neutral) {
(*mob)++;
if (p[u].nextpos == p[u].nextdir) pin = -1; /* oops new direction */
u = p[u].nextpos;
}
else if (pin < 0) {
if (board[u] == pawn || board[u] == king)
u = p[u].nextdir;
else {
if (p[u].nextpos != p[u].nextdir)
pin = u; /* not on the edge and on to find a pin */
u = p[u].nextpos;
}
}
else if (color[u] == c2 && (board[u] > piece || atk2[u] == 0))
{
if (color[pin] == c2)
{
*s += PINVAL;
if (atk2[pin] == 0 ||
atk1[pin] > control[board[pin]]+1)
++hung[c2];
}
else *s += XRAY;
pin = -1; /* new direction */
u = p[u].nextdir;
}
else {
pin = -1; /* new direction */
u = p[u].nextdir;
}
}
}
#endif
#if (NEWMOVE >= 5)
CaptureList(side,xside,ply)
short side,xside,ply;
{
register short u,sq;
register struct sqdata *p;
short i,piece,*PL;
struct leaf *node;
TrPnt[ply+1] = TrPnt[ply];
node = &Tree[TrPnt[ply]];
PL = PieceList[side];
for (i = 0; i <= PieceCnt[side]; i++)
{
sq = PL[i];
piece = board[sq];
p = posdata[side][piece][sq];
if (piece == pawn) {
u = p[sq].nextdir; /* follow captures thread */
while (u != sq) {
if (color[u] == xside) {
node->f = sq; node->t = u;
node->flags = capture;
if (u < 8 || u > 55)
{
node->flags |= promote;
node->score = valueQ;
}
else
node->score = value[board[u]] + svalue[board[u]] - piece;
++node;
++TrPnt[ply+1];
}
u = p[u].nextdir;
}
}
else {
u = p[sq].nextpos;
while (u != sq) {
if (color[u] == neutral)
u = p[u].nextpos;
else {
if (color[u] == xside) {
node->f = sq; node->t = u;
node->flags = capture;
node->score = value[board[u]] + svalue[board[u]] - piece;
++node;
++TrPnt[ply+1];
}
u = p[u].nextdir;
}
}
}
}
}
#endif
#if (NEWMOVE > 5)
GenMoves(ply,sq,side,xside)
short ply,sq,side,xside;
/*
Generate moves for a piece. The moves are taken from the
precalulated array posdata. If the board is free, next move
is choosen from nextpos else from nextdir.
*/
{
register short u,piece;
register struct sqdata *p;
piece = board[sq];
p = posdata[side][piece][sq];
if (piece == pawn) {
u = p[sq].nextdir; /* follow captures thread */
while (u != sq) {
if (color[u] == xside) LinkMove(ply,sq,u,xside);
u = p[u].nextdir;
}
u = p[sq].nextpos; /* and follow no captures thread */
while (u != sq) {
if (color[u] == neutral && (u != sq+16 || color[u-8] == neutral)
&& (u != sq-16 || color[u+8] == neutral)) {
LinkMove(ply,sq,u,xside);
}
u = p[u].nextpos;
}
}
else {
u = p[sq].nextpos;
while (u != sq) {
if (color[u] == neutral) {
LinkMove(ply,sq,u,xside);
u = p[u].nextpos;
}
else {
if (color[u] == xside) LinkMove(ply,sq,u,xside);
u = p[u].nextdir;
}
}
}
}
#endif