FICS 1.6.2

1 files changed, 1297 insertions, 0 deletions

diff --git a/FICS/movecheck.c b/FICS/movecheck.c
new file mode 100644
index 0000000..8d62486
--- /dev/null
+++ b/FICS/movecheck.c
@@ -0,0 +1,1297 @@
+/* movecheck.c
+ *
+ */
+
+/*
+    fics - An internet chess server.
+    Copyright (C) 1993  Richard V. Nash
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+*/
+
+/* Revision history:
+   name		email		yy/mm/dd	Change
+   Richard Nash	              	93/10/22	Created
+*/
+
+#include "stdinclude.h"
+
+#include "common.h"
+#include "movecheck.h"
+#include "algcheck.h"
+#include "board.h"
+#include "gamedb.h"
+#include "utils.h"
+#include "network.h"
+#include "playerdb.h"
+
+/* Simply tests if the input string is a move or not. */
+/* If it matches patterns below */
+/* Add to this list as you improve the move parser */
+/* MS_COMP e2e4 */
+/* MS_COMPDASH e2-e4 */
+/* MS_CASTLE o-o, o-o-o */
+/* Not done yet */
+/* MS_ALG e4, Nd5 Ncd5 */
+PUBLIC int is_move(char *mstr)
+{
+  int len = strlen(mstr);
+  if ((len > 3) && (mstr[len - 2] == '='))
+    len -= 2;
+
+  if (len == 4) {		/* Test for e2e4 */
+    if (isfile(mstr[0]) && isrank(mstr[1]) &&
+	isfile(mstr[2]) && isrank(mstr[3])) {
+      return MS_COMP;
+    }
+  }
+  if (len == 5) {		/* Test for e2-e4 */
+    if (isfile(mstr[0]) && isrank(mstr[1]) &&
+	(mstr[2] == '-') &&
+	isfile(mstr[3]) && isrank(mstr[4])) {
+      return MS_COMPDASH;
+    }
+  }
+  if (len == 3) {		/* Test for o-o */
+    if ((mstr[0] == 'o') && (mstr[1] == '-') && (mstr[2] == 'o')) {
+      return MS_KCASTLE;
+    }
+    if ((mstr[0] == 'O') && (mstr[1] == '-') && (mstr[2] == 'O')) {
+      return MS_KCASTLE;
+    }
+    if ((mstr[0] == '0') && (mstr[1] == '-') && (mstr[2] == '0')) {
+      return MS_KCASTLE;
+    }
+  }
+  if (len == 2) {		/* Test for oo */
+    if ((mstr[0] == 'o') && (mstr[1] == 'o')) {
+      return MS_KCASTLE;
+    }
+    if ((mstr[0] == 'O') && (mstr[1] == 'O')) {
+      return MS_KCASTLE;
+    }
+    if ((mstr[0] == '0') && (mstr[1] == '0')) {
+      return MS_KCASTLE;
+    }
+  }
+  if (len == 5) {		/* Test for o-o-o */
+    if ((mstr[0] == 'o') && (mstr[1] == '-') && (mstr[2] == 'o') && (mstr[3] == '-') && (mstr[4] == 'o')) {
+      return MS_QCASTLE;
+    }
+    if ((mstr[0] == 'O') && (mstr[1] == '-') && (mstr[2] == 'O') && (mstr[3] == '-') && (mstr[4] == 'O')) {
+      return MS_QCASTLE;
+    }
+    if ((mstr[0] == '0') && (mstr[1] == '-') && (mstr[2] == '0') && (mstr[3] == '-') && (mstr[4] == '0')) {
+      return MS_QCASTLE;
+    }
+  }
+  if (len == 3) {		/* Test for ooo */
+    if ((mstr[0] == 'o') && (mstr[1] == 'o') && (mstr[2] == 'o')) {
+      return MS_QCASTLE;
+    }
+    if ((mstr[0] == 'O') && (mstr[1] == 'O') && (mstr[2] == 'O')) {
+      return MS_QCASTLE;
+    }
+    if ((mstr[0] == '0') && (mstr[1] == '0') && (mstr[2] == '0')) {
+      return MS_QCASTLE;
+    }
+  }
+  return alg_is_move(mstr);
+}
+
+
+PUBLIC int NextPieceLoop(board_t b, int *f, int *r, int color)
+{
+  while (1) {
+    (*r) = (*r) + 1;
+    if (*r > 7) {
+      *r = 0;
+      *f = *f + 1;
+      if (*f > 7)
+	break;
+    }
+    if ((b[*f][*r] != NOPIECE) && iscolor(b[*f][*r], color))
+      return 1;
+  }
+  return 0;
+}
+
+PUBLIC int InitPieceLoop(board_t b, int *f, int *r, int color)
+{
+  *f = 0;
+  *r = -1;
+  return 1;
+}
+
+/* All of the routines assume that the obvious problems have been checked */
+/* See legal_move() */
+PRIVATE int legal_pawn_move( game_state_t *gs, int ff, int fr, int tf, int tr )
+{
+  if (ff == tf) {
+    if (gs->board[tf][tr] != NOPIECE) return 0;
+    if (gs->onMove == WHITE) {
+      if (tr - fr == 1) return 1;
+      if ((fr == 1) && (tr - fr == 2) && gs->board[ff][2]==NOPIECE) return 1;
+    } else {
+      if (fr - tr == 1) return 1;
+      if ((fr == 6) && (fr - tr == 2) && gs->board[ff][5]==NOPIECE) return 1;
+    }
+    return 0;
+  }
+  if (ff != tf) { /* Capture ? */
+    if ((ff - tf != 1) && (tf - ff != 1)) return 0;
+    if ((fr - tr != 1) && (tr - fr != 1)) return 0;
+    if (gs->onMove == WHITE) {
+      if (fr > tr) return 0;
+      if ((gs->board[tf][tr] != NOPIECE) && iscolor(gs->board[tf][tr],BLACK))
+        return 1;
+      if (gs->ep_possible[0][ff] == 1) {
+        if ((tf==ff+1) && (gs->board[ff+1][fr] == B_PAWN)) return 1;
+      } else if (gs->ep_possible[0][ff] == -1) {
+        if ((tf==ff-1) && (gs->board[ff-1][fr] == B_PAWN)) return 1;
+      }
+    } else {
+      if (tr > fr) return 0;
+      if ((gs->board[tf][tr] != NOPIECE) && iscolor(gs->board[tf][tr],WHITE))
+        return 1;
+      if (gs->ep_possible[1][ff] == 1) {
+        if ((tf==ff+1) && (gs->board[ff+1][fr] == W_PAWN)) return 1;
+      } else if (gs->ep_possible[1][ff] == -1) {
+        if ((tf==ff-1) && (gs->board[ff-1][fr] == W_PAWN)) return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+PRIVATE int legal_knight_move(game_state_t * gs, int ff, int fr, int tf, int tr)
+{
+  int dx, dy;
+
+  dx = ff - tf;
+  dy = fr - tr;
+  if ((dx == 2) || (dx == -2)) {
+    if ((dy == -1) || (dy == 1))
+      return 1;
+  }
+  if ((dy == 2) || (dy == -2)) {
+    if ((dx == -1) || (dx == 1))
+      return 1;
+  }
+  return 0;
+}
+
+PRIVATE int legal_bishop_move(game_state_t * gs, int ff, int fr, int tf, int tr)
+{
+  int dx, dy, x, y;
+  int startx, starty;
+  int count;
+  int incx, incy;
+
+  if (ff > tf) {
+    dx = ff - tf;
+    incx = -1;
+  } else {
+    dx = tf - ff;
+    incx = 1;
+  }
+  startx = ff + incx;
+  if (fr > tr) {
+    dy = fr - tr;
+    incy = -1;
+  } else {
+    dy = tr - fr;
+    incy = 1;
+  }
+  starty = fr + incy;
+  if (dx != dy)
+    return 0;			/* Not diagonal */
+  if (dx == 1)
+    return 1;			/* One square, ok */
+  count = dx - 1;
+  for (x = startx, y = starty; count; x += incx, y += incy, count--) {
+    if (gs->board[x][y] != NOPIECE)
+      return 0;
+  }
+  return 1;
+}
+
+PRIVATE int legal_rook_move(game_state_t * gs, int ff, int fr, int tf, int tr)
+{
+  int i;
+  int start, stop;
+
+  if (ff == tf) {
+    if (((fr - tr) == 1) || ((tr - fr) == 1))
+      return 1;
+    if (fr < tr) {
+      start = fr + 1;
+      stop = tr - 1;
+    } else {
+      start = tr + 1;
+      stop = fr - 1;
+    }
+    for (i = start; i <= stop; i++) {
+      if (gs->board[ff][i] != NOPIECE)
+	return 0;
+    }
+    return 1;
+  } else if (fr == tr) {
+    if (((ff - tf) == 1) || ((tf - ff) == 1))
+      return 1;
+    if (ff < tf) {
+      start = ff + 1;
+      stop = tf - 1;
+    } else {
+      start = tf + 1;
+      stop = ff - 1;
+    }
+    for (i = start; i <= stop; i++) {
+      if (gs->board[i][fr] != NOPIECE)
+	return 0;
+    }
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+PRIVATE int legal_queen_move(game_state_t * gs, int ff, int fr, int tf, int tr)
+{
+  return legal_rook_move(gs, ff, fr, tf, tr) || legal_bishop_move(gs, ff, fr, tf, tr);
+}
+
+/* Ckeck, if square (kf,kr) is attacked by enemy piece.
+ * Used in castling from/through check testing.
+ */
+
+/* new one from soso: */
+PRIVATE int is_square_attacked (game_state_t *gs, int kf, int kr)
+{
+  game_state_t fakeMove;
+
+  fakeMove = *gs;
+  fakeMove.board[4][kr] = NOPIECE;
+  fakeMove.board[kf][kr] = KING | fakeMove.onMove;
+  fakeMove.onMove = CToggle (fakeMove.onMove);
+  if (in_check(&fakeMove)) return 1;
+    else return 0;
+}
+
+/* old one:
+PRIVATE int is_square_attacked(game_state_t * gs, int kf, int kr)
+{
+  int f, r;
+  gs->onMove = CToggle(gs->onMove);
+
+  for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
+       NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
+    if (legal_move(gs, f, r, kf, kr)) {
+      gs->onMove = CToggle(gs->onMove);
+      return 1;
+    }
+  }
+  gs->onMove = CToggle(gs->onMove);
+  return 0;
+}
+*/
+
+PRIVATE int legal_king_move(game_state_t * gs, int ff, int fr, int tf, int tr)
+{
+  if (gs->onMove == WHITE) {
+    /* King side castling */
+    if ((fr == 0) && (tr == 0) && (ff == 4) && (tf == 6) && !gs->wkmoved
+	&& (!gs->wkrmoved) && (gs->board[5][0] == NOPIECE) &&
+	(gs->board[6][0] == NOPIECE) && (gs->board[7][0] == W_ROOK) &&
+	(!is_square_attacked(gs, 4, 0)) && (!is_square_attacked(gs, 5, 0))) {
+      return 1;
+    }
+    /* Queen side castling */
+    if ((fr == 0) && (tr == 0) && (ff == 4) && (tf == 2) && !gs->wkmoved
+	&& (!gs->wqrmoved) && (gs->board[3][0] == NOPIECE) &&
+	(gs->board[2][0] == NOPIECE) && (gs->board[1][0] == NOPIECE) &&
+	(gs->board[0][0] == W_ROOK) &&
+	(!is_square_attacked(gs, 4, 0)) && (!is_square_attacked(gs, 3, 0))) {
+      return 1;
+    }
+  } else {			/* Black */
+    /* King side castling */
+    if ((fr == 7) && (tr == 7) && (ff == 4) && (tf == 6) && !gs->bkmoved
+	&& (!gs->bkrmoved) && (gs->board[5][7] == NOPIECE) &&
+	(gs->board[6][7] == NOPIECE) && (gs->board[7][7] == B_ROOK) &&
+	(!is_square_attacked(gs, 4, 7)) && (!is_square_attacked(gs, 5, 7))) {
+      return 1;
+    }
+    /* Queen side castling */
+    if ((fr == 7) && (tr == 7) && (ff == 4) && (tf == 2) && (!gs->bkmoved)
+	&& (!gs->bqrmoved) && (gs->board[3][7] == NOPIECE) &&
+	(gs->board[2][7] == NOPIECE) && (gs->board[1][7] == NOPIECE) &&
+	(gs->board[0][7] == B_ROOK) &&
+	(!is_square_attacked(gs, 4, 7)) && (!is_square_attacked(gs, 3, 7))) {
+      return 1;
+    }
+  }
+  if (((ff - tf) > 1) || ((tf - ff) > 1))
+    return 0;
+  if (((fr - tr) > 1) || ((tr - fr) > 1))
+    return 0;
+  return 1;
+}
+
+PRIVATE void add_pos(int tof, int tor, int *posf, int *posr, int *numpos)
+{
+  posf[*numpos] = tof;
+  posr[*numpos] = tor;
+  (*numpos)++;
+}
+
+PRIVATE void possible_pawn_moves(game_state_t * gs,
+				  int onf, int onr,
+				  int *posf, int *posr, int *numpos)
+{
+  if (gs->onMove == WHITE) {
+    if (gs->board[onf][onr + 1] == NOPIECE) {
+      add_pos(onf, onr + 1, posf, posr, numpos);
+      if ((onr == 1) && (gs->board[onf][onr + 2] == NOPIECE))
+	add_pos(onf, onr + 2, posf, posr, numpos);
+    }
+    if ((onf > 0) && (gs->board[onf - 1][onr + 1] != NOPIECE) &&
+	(iscolor(gs->board[onf - 1][onr + 1], BLACK)))
+      add_pos(onf - 1, onr + 1, posf, posr, numpos);
+    if ((onf < 7) && (gs->board[onf + 1][onr + 1] != NOPIECE) &&
+	(iscolor(gs->board[onf + 1][onr + 1], BLACK)))
+      add_pos(onf + 1, onr + 1, posf, posr, numpos);
+    if (gs->ep_possible[0][onf] == -1)
+      add_pos(onf - 1, onr + 1, posf, posr, numpos);
+    if (gs->ep_possible[0][onf] == 1)
+      add_pos(onf + 1, onr + 1, posf, posr, numpos);
+  } else {
+    if (gs->board[onf][onr - 1] == NOPIECE) {
+      add_pos(onf, onr - 1, posf, posr, numpos);
+      if ((onr == 6) && (gs->board[onf][onr - 2] == NOPIECE))
+	add_pos(onf, onr - 2, posf, posr, numpos);
+    }
+    if ((onf > 0) && (gs->board[onf - 1][onr - 1] != NOPIECE) &&
+	(iscolor(gs->board[onf - 1][onr - 1], WHITE)))
+      add_pos(onf - 1, onr - 1, posf, posr, numpos);
+/* loon: changed what looks like a typo, here's the original line:
+      add_pos(onf - 1, onr + 1, posf, posr, numpos);
+*/
+    if ((onf < 7) && (gs->board[onf + 1][onr - 1] != NOPIECE) &&
+	(iscolor(gs->board[onf + 1][onr - 1], WHITE)))
+      add_pos(onf + 1, onr - 1, posf, posr, numpos);
+    if (gs->ep_possible[1][onf] == -1)
+      add_pos(onf - 1, onr - 1, posf, posr, numpos);
+    if (gs->ep_possible[1][onf] == 1)
+      add_pos(onf + 1, onr - 1, posf, posr, numpos);
+  }
+}
+
+PRIVATE void possible_knight_moves(game_state_t * gs,
+				    int onf, int onr,
+				    int *posf, int *posr, int *numpos)
+{
+  static int knightJumps[8][2] = {{-1, 2}, {1, 2}, {2, -1}, {2, 1},
+  {-1, -2}, {1, -2}, {-2, 1}, {-2, -1}};
+  int f, r;
+  int j;
+
+  for (j = 0; j < 8; j++) {
+    f = knightJumps[j][0] + onf;
+    r = knightJumps[j][1] + onr;
+    if ((f < 0) || (f > 7))
+      continue;
+    if ((r < 0) || (r > 7))
+      continue;
+    if ((gs->board[f][r] == NOPIECE) ||
+	(iscolor(gs->board[f][r], CToggle(gs->onMove))))
+      add_pos(f, r, posf, posr, numpos);
+  }
+}
+
+PRIVATE void possible_bishop_moves(game_state_t * gs,
+				    int onf, int onr,
+				    int *posf, int *posr, int *numpos)
+{
+  int f, r;
+
+  /* Up Left */
+  f = onf;
+  r = onr;
+  while (1) {
+    f--;
+    r++;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+  /* Up Right */
+  f = onf;
+  r = onr;
+  while (1) {
+    f++;
+    r++;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+  /* Down Left */
+  f = onf;
+  r = onr;
+  while (1) {
+    f--;
+    r--;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+  /* Down Right */
+  f = onf;
+  r = onr;
+  while (1) {
+    f++;
+    r--;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+}
+
+PRIVATE void possible_rook_moves(game_state_t * gs,
+				  int onf, int onr,
+				  int *posf, int *posr, int *numpos)
+{
+  int f, r;
+
+  /* Left */
+  f = onf;
+  r = onr;
+  while (1) {
+    f--;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+  /* Right */
+  f = onf;
+  r = onr;
+  while (1) {
+    f++;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+  /* Up */
+  f = onf;
+  r = onr;
+  while (1) {
+    r++;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+  /* Down */
+  f = onf;
+  r = onr;
+  while (1) {
+    r--;
+    if ((f < 0) || (f > 7))
+      break;
+    if ((r < 0) || (r > 7))
+      break;
+    if ((gs->board[f][r] != NOPIECE) && (iscolor(gs->board[f][r], gs->onMove)))
+      break;
+    add_pos(f, r, posf, posr, numpos);
+    if (gs->board[f][r] != NOPIECE)
+      break;
+  }
+}
+
+PRIVATE void possible_queen_moves(game_state_t * gs,
+				   int onf, int onr,
+				   int *posf, int *posr, int *numpos)
+{
+  possible_rook_moves(gs, onf, onr, posf, posr, numpos);
+  possible_bishop_moves(gs, onf, onr, posf, posr, numpos);
+}
+
+PRIVATE void possible_king_moves(game_state_t * gs,
+				  int onf, int onr,
+				  int *posf, int *posr, int *numpos)
+{
+  static int kingJumps[8][2] = {{-1, -1}, {0, -1}, {1, -1}, {-1, 1},
+  {0, 1}, {1, 1}, {-1, 0}, {1, 0}};
+  int f, r;
+  int j;
+
+  for (j = 0; j < 8; j++) {
+    f = kingJumps[j][0] + onf;
+    r = kingJumps[j][1] + onr;
+    if ((f < 0) || (f > 7))
+      continue;
+    if ((r < 0) || (r > 7))
+      continue;
+    if ((gs->board[f][r] == NOPIECE) ||
+	(iscolor(gs->board[f][r], CToggle(gs->onMove))))
+      add_pos(f, r, posf, posr, numpos);
+  }
+}
+
+/* Doesn't check for check */
+PUBLIC int legal_move(game_state_t * gs,
+		       int fFile, int fRank,
+		       int tFile, int tRank)
+{
+  int move_piece;
+  int legal;
+
+  if (fFile == ALG_DROP) {
+    move_piece = fRank;
+    if (move_piece == KING)
+      return 0;
+    if (gs->holding[gs->onMove==WHITE ? 0 : 1][move_piece-1] == 0)
+      return 0;
+    if (gs->board[tFile][tRank] != NOPIECE)
+      return 0;
+    if (move_piece == PAWN && (tRank == 0 || tRank == 7))
+      return 0;
+    return 1;
+  } else {
+    move_piece = piecetype(gs->board[fFile][fRank]);
+  }
+  if (gs->board[fFile][fRank] == NOPIECE)
+    return 0;
+  if (!iscolor(gs->board[fFile][fRank], gs->onMove))	/* Wrong color */
+    return 0;
+  if ((gs->board[tFile][tRank] != NOPIECE) &&
+      iscolor(gs->board[tFile][tRank], gs->onMove))	/* Can't capture own */
+    return 0;
+  if ((fFile == tFile) && (fRank == tRank))	/* Same square */
+    return 0;
+  switch (move_piece) {
+  case PAWN:
+    legal = legal_pawn_move(gs, fFile, fRank, tFile, tRank);
+    break;
+  case KNIGHT:
+    legal = legal_knight_move(gs, fFile, fRank, tFile, tRank);
+    break;
+  case BISHOP:
+    legal = legal_bishop_move(gs, fFile, fRank, tFile, tRank);
+    break;
+  case ROOK:
+    legal = legal_rook_move(gs, fFile, fRank, tFile, tRank);
+    break;
+  case QUEEN:
+    legal = legal_queen_move(gs, fFile, fRank, tFile, tRank);
+    break;
+  case KING:
+    legal = legal_king_move(gs, fFile, fRank, tFile, tRank);
+    break;
+  default:
+    return 0;
+    break;
+  }
+  return legal;
+}
+
+
+/* This fills in the rest of the mt structure once it is determined that
+ * the move is legal. Returns MOVE_ILLEGAL if move leaves you in check */
+PRIVATE int move_calculate(game_state_t * gs, move_t * mt, int promote)
+{
+  game_state_t fakeMove;
+
+  mt->pieceCaptured = gs->board[mt->toFile][mt->toRank];
+  mt->enPassant = 0;		/* Don't know yet, let execute move take care
+				   of it */
+  if (mt->fromFile == ALG_DROP) {
+    mt->piecePromotionTo = NOPIECE;
+    sprintf(mt->moveString, "%s/%c%c-%c%d",
+	    wpstring[mt->fromRank],
+		DROP_CHAR, DROP_CHAR,
+	    mt->toFile + 'a', mt->toRank + 1);
+  } else {
+  if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == PAWN) &&
+      ((mt->toRank == 0) || (mt->toRank == 7))) {
+    mt->piecePromotionTo = promote |
+      (colorval(gs->board[mt->fromFile][mt->fromRank]));
+  } else {
+    mt->piecePromotionTo = NOPIECE;
+  }
+  if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == PAWN) &&
+   ((mt->fromRank - mt->toRank == 2) || (mt->toRank - mt->fromRank == 2))) {
+    mt->doublePawn = mt->fromFile;
+  } else {
+    mt->doublePawn = -1;
+  }
+  if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == KING) &&
+      (mt->fromFile == 4) && (mt->toFile == 2)) {
+    sprintf(mt->moveString, "o-o-o");
+  } else if ((piecetype(gs->board[mt->fromFile][mt->fromRank]) == KING) &&
+	     (mt->fromFile == 4) && (mt->toFile == 6)) {
+    sprintf(mt->moveString, "o-o");
+  } else {
+    sprintf(mt->moveString, "%s/%c%d-%c%d",
+	    wpstring[piecetype(gs->board[mt->fromFile][mt->fromRank])],
+	    mt->fromFile + 'a', mt->fromRank + 1,
+	    mt->toFile + 'a', mt->toRank + 1);
+  }
+  }
+  /* Replace this with an algabraic de-parser */
+
+  sprintf(mt->algString, alg_unparse(gs, mt));
+  fakeMove = *gs;
+  /* Calculates enPassant also */
+  execute_move(&fakeMove, mt, 0);
+
+  /* Does making this move leave ME in check? */
+  if (in_check(&fakeMove))
+    return MOVE_ILLEGAL;
+  /* IanO: bughouse variants: drop cannot be check/checkmate */
+
+  return MOVE_OK;
+}
+
+PUBLIC int legal_andcheck_move(game_state_t * gs,
+			        int fFile, int fRank,
+			        int tFile, int tRank)
+{
+  move_t mt;
+  if (!legal_move(gs, fFile, fRank, tFile, tRank))
+    return 0;
+  mt.color = gs->onMove;
+  mt.fromFile = fFile;
+  mt.fromRank = fRank;
+  mt.toFile = tFile;
+  mt.toRank = tRank;
+  /* This should take into account a pawn promoting to another piece */
+  if (move_calculate(gs, &mt, QUEEN) == MOVE_OK)
+    return 1;
+  else
+    return 0;
+}
+
+PUBLIC int in_check(game_state_t * gs)
+{
+  int f, r;
+  int kf = -1, kr = -1;
+
+  /* Find the king */
+  if (gs->onMove == WHITE) {
+    for (f = 0; f < 8 && kf < 0; f++)
+      for (r = 0; r < 8 && kf < 0; r++)
+	if (gs->board[f][r] == B_KING) {
+	  kf = f;
+	  kr = r;
+	}
+  } else {
+    for (f = 0; f < 8 && kf < 0; f++)
+      for (r = 0; r < 8 && kf < 0; r++)
+	if (gs->board[f][r] == W_KING) {
+	  kf = f;
+	  kr = r;
+	}
+  }
+  if (kf < 0) {
+    fprintf(stderr, "FICS: Error game with no king!\n");
+    return 0;
+  }
+  for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
+       NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
+    if (legal_move(gs, f, r, kf, kr)) {	/* In Check? */
+      return 1;
+    }
+  }
+  return 0;
+}
+
+PRIVATE int has_legal_move(game_state_t * gs)
+{
+  int i;
+  int f, r;
+  int kf,kr;
+  int possiblef[500], possibler[500];
+  int numpossible = 0;
+
+  for (InitPieceLoop(gs->board, &f, &r, gs->onMove);
+       NextPieceLoop(gs->board, &f, &r, gs->onMove);) {
+    switch (piecetype(gs->board[f][r])) {
+    case PAWN:
+      possible_pawn_moves(gs, f, r, possiblef, possibler, &numpossible);
+      break;
+    case KNIGHT:
+      possible_knight_moves(gs, f, r, possiblef, possibler, &numpossible);
+      break;
+    case BISHOP:
+      possible_bishop_moves(gs, f, r, possiblef, possibler, &numpossible);
+      break;
+    case ROOK:
+      possible_rook_moves(gs, f, r, possiblef, possibler, &numpossible);
+      break;
+    case QUEEN:
+      possible_queen_moves(gs, f, r, possiblef, possibler, &numpossible);
+      break;
+    case KING:
+      kf = f;
+      kr = r;
+      possible_king_moves(gs, f, r, possiblef, possibler, &numpossible);
+      break;
+    }
+    if (numpossible >= 500) {
+      fprintf(stderr, "FICS: Possible move overrun\n");
+    }
+    for (i = 0; i < numpossible; i++)
+      if (legal_andcheck_move(gs, f, r, possiblef[i], possibler[i])) {
+	return 1;
+      }
+  }
+
+  /* IanO:  if we got here, then kf and kr must be set */
+  if (gs->gameNum >=0 && garray[gs->gameNum].link >= 0) {
+    /* bughouse: potential drops as check interpositions */
+    gs->holding[gs->onMove==WHITE ? 0 : 1][QUEEN - 1]++;
+    for (f=kf-1; f<=kf+1; f++) for (r=kr-1; r<=kr+1; r++) {
+      if (f>=0 && f<8 && r>=0 && r<8 && gs->board[f][r] == NOPIECE) {
+	/* try a drop next to the king */
+	if (legal_andcheck_move(gs, ALG_DROP, QUEEN, f, r)) {
+	  gs->holding[gs->onMove==WHITE ? 0 : 1][QUEEN - 1]--;
+	  return 1;
+	}
+      }
+    }
+    gs->holding[gs->onMove==WHITE ? 0 : 1][QUEEN - 1]--;
+  }
+
+/* don't think this works right... 9.30.95
+  printf("NO LEGAL MOVE!\n");
+*/
+  fprintf(stderr, "FICS: NO LEGAL MOVE!\n");
+  return 0;
+}
+
+/* This will end up being a very complicated function */
+PUBLIC int parse_move(char *mstr, game_state_t * gs, move_t * mt, int promote)
+{
+  int type = is_move(mstr);
+  int result;
+
+  mt->color = gs->onMove;
+  switch (type) {
+  case MS_NOTMOVE:
+    return MOVE_ILLEGAL;
+    break;
+  case MS_COMP:
+    mt->fromFile = mstr[0] - 'a';
+    mt->fromRank = mstr[1] - '1';
+    mt->toFile = mstr[2] - 'a';
+    mt->toRank = mstr[3] - '1';
+    break;
+  case MS_COMPDASH:
+    mt->fromFile = mstr[0] - 'a';
+    mt->fromRank = mstr[1] - '1';
+    mt->toFile = mstr[3] - 'a';
+    mt->toRank = mstr[4] - '1';
+    break;
+  case MS_KCASTLE:
+    mt->fromFile = 4;
+    mt->toFile = 6;
+    if (gs->onMove == WHITE) {
+      mt->fromRank = 0;
+      mt->toRank = 0;
+    } else {
+      mt->fromRank = 7;
+      mt->toRank = 7;
+    }
+    break;
+  case MS_QCASTLE:
+    mt->fromFile = 4;
+    mt->toFile = 2;
+    if (gs->onMove == WHITE) {
+      mt->fromRank = 0;
+      mt->toRank = 0;
+    } else {
+      mt->fromRank = 7;
+      mt->toRank = 7;
+    }
+    break;
+  case MS_ALG:
+    /* Fills in the mt structure */
+    if ((result = alg_parse_move(mstr, gs, mt)) != MOVE_OK)
+      return result;
+    break;
+  default:
+    return MOVE_ILLEGAL;
+    break;
+  }
+  if (!legal_move(gs, mt->fromFile, mt->fromRank, mt->toFile, mt->toRank)) {
+    return MOVE_ILLEGAL;
+  }
+  return move_calculate(gs, mt, promote);
+}
+
+/* Returns MOVE_OK, MOVE_NOMATERIAL, MOVE_CHECKMATE, or MOVE_STALEMATE */
+/* check_game_status prevents recursion */
+PUBLIC int execute_move(game_state_t * gs, move_t * mt, int check_game_status)
+{
+  int movedPiece;
+  int tookPiece;
+  int i, j, foobar;
+
+  if (mt->fromFile == ALG_DROP) {
+    movedPiece = mt->fromRank;
+    tookPiece = NOPIECE;
+    gs->holding[gs->onMove==WHITE ? 0 : 1][movedPiece-1]--;
+    gs->board[mt->toFile][mt->toRank] = movedPiece | gs->onMove;
+    if (gs->gameNum >= 0)
+      gs->lastIrreversable = garray[gs->gameNum].numHalfMoves;
+  } else {
+  movedPiece = gs->board[mt->fromFile][mt->fromRank];
+  tookPiece = gs->board[mt->toFile][mt->toRank];
+  if (mt->piecePromotionTo == NOPIECE) {
+    gs->board[mt->toFile][mt->toRank] = gs->board[mt->fromFile][mt->fromRank];
+  } else {
+    gs->board[mt->toFile][mt->toRank] = mt->piecePromotionTo | gs->onMove;
+  }
+  gs->board[mt->fromFile][mt->fromRank] = NOPIECE;
+  /* Check if irreversable */
+  if ((piecetype(movedPiece) == PAWN) || (tookPiece != NOPIECE)) {
+    if (gs->gameNum >= 0)
+      gs->lastIrreversable = garray[gs->gameNum].numHalfMoves;
+  }
+  /* Check if this move is en-passant */
+  if ((piecetype(movedPiece) == PAWN) && (mt->fromFile != mt->toFile) &&
+      (tookPiece == NOPIECE)) {
+    if (gs->onMove == WHITE) {
+      mt->pieceCaptured = B_PAWN;
+    } else {
+      mt->pieceCaptured = W_PAWN;
+    }
+    if (mt->fromFile > mt->toFile) {
+      mt->enPassant = -1;
+    } else {
+      mt->enPassant = 1;
+    }
+    gs->board[mt->toFile][mt->fromRank] = NOPIECE;
+  }
+  /* Check en-passant flags for next moves */
+  for (i = 0; i < 8; i++) {
+    gs->ep_possible[0][i] = 0;
+    gs->ep_possible[1][i] = 0;
+  }
+/* Added by Sparky 3/16/95
+
+   From soso@Viktoria.drp.fmph.uniba.sk Thu Mar 16 13:08:51 1995
+   Subject: Re: To DAV: enpassant prob. again
+   To: chess@caissa.onenet.net (ICS)
+   Date: Thu, 16 Mar 1995 20:06:20 +0100 (MET)
+
+   Yeah !
+   There was bug in other part of code:
+
+   movecheck.c , line about 800:
+
+     if (gs->onMove == WHITE) {
+        if ((mt->toFile+1 < 7 ) ....  should be : (mt->toFile < 7 ) }
+*/
+
+  if ((piecetype(movedPiece) == PAWN) &&
+   ((mt->fromRank == mt->toRank + 2) || (mt->fromRank + 2 == mt->toRank))) {
+    /* Should turn on enpassent flag if possible */
+    if (gs->onMove == WHITE) {
+      if ((mt->toFile < 7) && gs->board[mt->toFile + 1][3] == B_PAWN) {
+	gs->ep_possible[1][mt->toFile + 1] = -1;
+      }
+      if ((mt->toFile - 1 >= 0) && gs->board[mt->toFile - 1][3] == B_PAWN) {
+	gs->ep_possible[1][mt->toFile - 1] = 1;
+      }
+    } else {
+      if ((mt->toFile < 7) && gs->board[mt->toFile + 1][4] == W_PAWN) {
+	gs->ep_possible[0][mt->toFile + 1] = -1;
+      }
+      if ((mt->toFile - 1 >= 0) && gs->board[mt->toFile - 1][4] == W_PAWN) {
+	gs->ep_possible[0][mt->toFile - 1] = 1;
+      }
+    }
+  }
+  if ((piecetype(movedPiece) == ROOK) && (mt->fromFile == 0)) {
+    if ((mt->fromRank == 0) && (gs->onMove == WHITE))
+      gs->wqrmoved = 1;
+    if ((mt->fromRank == 7) && (gs->onMove == BLACK))
+      gs->bqrmoved = 1;
+  }
+  if ((piecetype(movedPiece) == ROOK) && (mt->fromFile == 7)) {
+    if ((mt->fromRank == 0) && (gs->onMove == WHITE))
+      gs->wkrmoved = 1;
+    if ((mt->fromRank == 7) && (gs->onMove == BLACK))
+      gs->bkrmoved = 1;
+  }
+  if (piecetype(movedPiece) == KING) {
+    if (gs->onMove == WHITE)
+      gs->wkmoved = 1;
+    else
+      gs->bkmoved = 1;
+  }
+  if ((piecetype(movedPiece) == KING) &&
+      ((mt->fromFile == 4) && ((mt->toFile == 6)))) {	/* Check for KS castling */
+    gs->board[5][mt->toRank] = gs->board[7][mt->toRank];
+    gs->board[7][mt->toRank] = NOPIECE;
+  }
+  if ((piecetype(movedPiece) == KING) &&
+      ((mt->fromFile == 4) && ((mt->toFile == 2)))) {	/* Check for QS castling */
+    gs->board[3][mt->toRank] = gs->board[0][mt->toRank];
+    gs->board[0][mt->toRank] = NOPIECE;
+  }
+  }
+  if (gs->onMove == BLACK)
+    gs->moveNum++;
+
+  if (check_game_status) {
+    /* Does this move result in check? */
+    if (in_check(gs)) {
+      /* Check for checkmate */
+      gs->onMove = CToggle(gs->onMove);
+      if (!has_legal_move(gs))
+	return MOVE_CHECKMATE;
+    } else {
+      /* Check for stalemate */
+      gs->onMove = CToggle(gs->onMove);
+      if (!has_legal_move(gs))
+	return MOVE_STALEMATE;
+/* loon: check for insufficient mating material, first try */
+      foobar = 0;
+      for (i=0; i<8; i++) {
+        for (j=0; j<8; j++) {
+          switch(piecetype(gs->board[i][j])) {
+            case KNIGHT:
+            case BISHOP:
+              foobar++;
+              break;
+            case KING:
+	    case NOPIECE:
+	      break;
+            default:
+              foobar = 2;
+              break;
+          }
+        }
+      }
+      if (foobar < 2)
+        return MOVE_NOMATERIAL;
+    }
+  } else {
+    gs->onMove = CToggle(gs->onMove);
+  }
+  return MOVE_OK;
+}
+
+PUBLIC int backup_move(int g, int mode)
+{
+  game_state_t *gs;
+  move_t *m, *m1;
+  int now, i;
+
+  if (garray[g].link >= 0)	/*IanO: not implemented for bughouse yet */
+    return MOVE_ILLEGAL;
+  if (garray[g].numHalfMoves < 1)
+    return MOVE_ILLEGAL;
+  gs = &garray[g].game_state;
+  m = (mode==REL_GAME) ? &garray[g].moveList[garray[g].numHalfMoves - 1] : 
+                         &garray[g].examMoveList[garray[g].numHalfMoves - 1];
+  if (m->toFile < 0) {
+    return MOVE_ILLEGAL;
+  }
+  gs->board[m->fromFile][m->fromRank] = gs->board[m->toFile][m->toRank];
+  if (m->piecePromotionTo != NOPIECE) {
+    gs->board[m->fromFile][m->fromRank] = PAWN |
+      colorval(gs->board[m->fromFile][m->fromRank]);
+  }
+  /******************
+     When takeback a _first_ move of rook, the ??rmoved variable
+     must be cleared . To check, if the move is first, we should
+     scan moveList.
+  *******************/
+  if (piecetype(gs->board[m->fromFile][m->fromRank]) == ROOK) {
+    if (m->color == WHITE) {
+      if ((m->fromFile == 0) && (m->fromRank == 0)) {
+	for (i = 2; i < garray[g].numHalfMoves - 1; i += 2) {
+	  m1 = (mode==REL_GAME) ? &garray[g].moveList[i] : &garray[g].examMoveList[i];
+	  if ((m1->fromFile == 0) && (m1->fromRank == 0))
+	    break;
+	}
+	if (i == garray[g].numHalfMoves - 1)
+	  gs->wqrmoved = 0;
+      }
+      if ((m->fromFile == 7) && (m->fromRank == 0)) {
+	for (i = 2; i < garray[g].numHalfMoves - 1; i += 2) {
+	  m1 = (mode==REL_GAME) ? &garray[g].moveList[i] : &garray[g].examMoveList[i];
+	  if ((m1->fromFile == 7) && (m1->fromRank == 0))
+	    break;
+	}
+	if (i == garray[g].numHalfMoves - 1)
+	  gs->wkrmoved = 0;
+      }
+    } else {
+      if ((m->fromFile == 0) && (m->fromRank == 7)) {
+	for (i = 3; i < garray[g].numHalfMoves - 1; i += 2) {
+	  m1 = (mode==REL_GAME) ? &garray[g].moveList[i] : &garray[g].examMoveList[i];
+	  if ((m1->fromFile == 0) && (m1->fromRank == 0))
+	    break;
+	}
+	if (i == garray[g].numHalfMoves - 1)
+	  gs->bqrmoved = 0;
+      }
+      if ((m->fromFile == 7) && (m->fromRank == 7)) {
+	for (i = 3; i < garray[g].numHalfMoves - 1; i += 2) {
+	  m1 = (mode==REL_GAME) ? &garray[g].moveList[i] : &garray[g].examMoveList[i];
+	  if ((m1->fromFile == 7) && (m1->fromRank == 0))
+	    break;
+	}
+	if (i == garray[g].numHalfMoves - 1)
+	  gs->bkrmoved = 0;
+      }
+    }
+  }
+  if (piecetype(gs->board[m->fromFile][m->fromRank]) == KING) {
+    gs->board[m->toFile][m->toRank] = m->pieceCaptured;
+
+    if (m->toFile - m->fromFile == 2) {
+      gs->board[7][m->fromRank] = ROOK |
+	colorval(gs->board[m->fromFile][m->fromRank]);
+      gs->board[5][m->fromRank] = NOPIECE;
+
+      /********
+         If takeback a castling, the appropriates ??moved variables
+         must be cleared
+      ********/
+      if (m->color == WHITE) {
+	gs->wkmoved = 0;
+	gs->wkrmoved = 0;
+      } else {
+	gs->bkmoved = 0;
+	gs->bkrmoved = 0;
+      }
+      goto cleanupMove;
+    }
+    if (m->fromFile - m->toFile == 2) {
+      gs->board[0][m->fromRank] = ROOK |
+	colorval(gs->board[m->fromFile][m->fromRank]);
+      gs->board[3][m->fromRank] = NOPIECE;
+
+      /**********
+         If takeback a castling, the appropriate ??moved variables
+         must be cleared
+      ***********/
+      if (m->color == WHITE) {
+	gs->wkmoved = 0;
+	gs->wqrmoved = 0;
+      } else {
+	gs->bkmoved = 0;
+	gs->bqrmoved = 0;
+      }
+      goto cleanupMove;
+    }
+    /******************
+       When takeback a _first_ move of king (not the castling),
+       the ?kmoved variable must be cleared . To check, if the move is first,
+       we should scan moveList.
+    *******************/
+
+    if (m->color == WHITE) {
+
+      if ((m->fromFile == 4) && (m->fromRank == 0)) {
+	for (i = 2; i < garray[g].numHalfMoves - 1; i += 2) {
+	  m1 = (mode==REL_GAME) ? &garray[g].moveList[i] : &garray[g].examMoveList[i];
+	  if ((m1->fromFile == 4) && (m1->fromRank == 0))
+	    break;
+	}
+	if (i == garray[g].numHalfMoves - 1)
+	  gs->wkmoved = 0;
+      }
+    } else {
+      if ((m->fromFile == 4) && (m->fromRank == 7)) {
+	for (i = 3; i < garray[g].numHalfMoves - 1; i += 2) {
+	  m1 = (mode==REL_GAME) ? &garray[g].moveList[i] : &garray[g].examMoveList[i];
+	  if ((m1->fromFile == 4) && (m1->fromRank == 7))
+	    break;
+	}
+	if (i == garray[g].numHalfMoves - 1)
+	  gs->bkmoved = 0;
+      }
+    }
+  }
+  if (m->enPassant) {		/* Do enPassant */
+    gs->board[m->toFile][m->fromRank] = PAWN |
+      (colorval(gs->board[m->fromFile][m->fromRank]) == WHITE ? BLACK : WHITE);
+    gs->board[m->toFile][m->toRank] = NOPIECE;
+    /* Should set the enpassant array, but I don't care right now */
+    goto cleanupMove;
+  }
+  gs->board[m->toFile][m->toRank] = m->pieceCaptured;
+cleanupMove:
+  if (garray[g].status != GAME_EXAMINE) {
+    game_update_time(g);
+  }
+  garray[g].numHalfMoves--;
+  if (garray[g].status != GAME_EXAMINE) {
+    if (garray[g].wInitTime) {	/* Don't update times in untimed games */
+      now = tenth_secs();
+
+#ifdef TIMESEAL
+
+      if (m->color == WHITE) {
+        if (con[parray[garray[g].white].socket].timeseal) {  /* white uses timeseal? */      
+          garray[g].wRealTime += (m->tookTime * 100); 
+          garray[g].wRealTime -= (garray[g].wIncrement * 100);
+          garray[g].wTime = garray[g].wRealTime / 100;
+          if (con[parray[garray[g].black].socket].timeseal) { /* opp uses timeseal? */
+            garray[g].bTime = garray[g].bRealTime / 100;
+	  } else {    /* opp has no timeseal */
+            garray[g].bTime += (garray[g].lastDecTime - garray[g].lastMoveTime);
+	  }
+	} else {  /* white has no timeseal */
+          garray[g].wTime += m->tookTime;
+          garray[g].wTime -= garray[g].wIncrement;
+          if (con[parray[garray[g].black].socket].timeseal) { /* opp uses timeseal? */
+            garray[g].bTime = garray[g].bRealTime / 100;
+	  } else {    /* opp has no timeseal */
+            garray[g].bTime += (garray[g].lastDecTime - garray[g].lastMoveTime);
+	  }
+	}
+      } else {
+        if (con[parray[garray[g].black].socket].timeseal) {  /* black uses timeseal? */
+          garray[g].bRealTime += (m->tookTime * 100);
+          garray[g].bRealTime -= (garray[g].wIncrement * 100);
+          garray[g].bTime = garray[g].bRealTime / 100;
+          if (con[parray[garray[g].white].socket].timeseal) { /* opp uses timeseal? */
+            garray[g].wTime = garray[g].wRealTime / 100;
+	  } else {    /* opp has no timeseal */
+            garray[g].wTime += (garray[g].lastDecTime - garray[g].lastMoveTime);
+	  }
+	} else {  /* black has no timeseal */
+          garray[g].bTime += m->tookTime;
+          if (!garray[g].bIncrement)
+            garray[g].bTime -= garray[g].wIncrement;
+          else
+  	    garray[g].bTime -= garray[g].bIncrement;
+          if (con[parray[garray[g].white].socket].timeseal) { /* opp uses timeseal? */
+            garray[g].wTime = garray[g].wRealTime / 100;
+	  } else {    /* opp has no timeseal */
+            garray[g].wTime += (garray[g].lastDecTime - garray[g].lastMoveTime);
+	  }
+	}
+      }
+
+#else
+
+      if (m->color == WHITE) {
+        garray[g].wTime += m->tookTime;
+        garray[g].wTime = garray[g].wTime - garray[g].wIncrement;
+        garray[g].bTime += (garray[g].lastDecTime - garray[g].lastMoveTime);
+      } else {
+        garray[g].bTime += m->tookTime;
+        if (!garray[g].bIncrement)
+          garray[g].bTime = garray[g].bTime - garray[g].wIncrement;
+        else
+	  garray[g].bTime = garray[g].bTime - garray[g].bIncrement;
+        garray[g].wTime += (garray[g].lastDecTime - garray[g].lastMoveTime);
+      }
+
+#endif
+
+      if (garray[g].numHalfMoves == 0)
+        garray[g].timeOfStart = now;
+      garray[g].lastMoveTime = now;
+      garray[g].lastDecTime = now;
+    }
+  }
+  if (gs->onMove == BLACK)
+    gs->onMove = WHITE;
+  else {
+    gs->onMove = BLACK;
+    gs->moveNum--;
+  }
+
+  /******* Here begins the patch : ********************************
+     Takeback of last move is done already, it's time to update enpassant
+     array.  (patch from Soso, added by Sparky 3/17/95)
+  ********/
+
+  if (garray[g].numHalfMoves > 0) {
+    m1 = (mode==REL_GAME) ? &garray[g].moveList[garray[g].numHalfMoves - 1] : 
+                            &garray[g].examMoveList[garray[g].numHalfMoves - 1];
+    if (piecetype(gs->board[m1->toFile][m1->toRank]) == PAWN) {
+      if ((m1->toRank - m1->fromRank) == 2) {
+	if ((m1->toFile < 7) && gs->board[m1->toFile + 1][3] == B_PAWN) {
+	  gs->ep_possible[1][m1->toFile + 1] = -1;
+	}
+	if ((m1->toFile - 1 >= 0) && gs->board[m1->toFile - 1][3] == B_PAWN) {
+	  gs->ep_possible[1][m1->toFile - 1] = 1;
+	}
+      }
+      if ((m1->toRank - m1->fromRank) == -2) {
+	if ((m1->toFile < 7) && gs->board[m1->toFile + 1][4] == W_PAWN) {
+	  gs->ep_possible[0][m1->toFile + 1] = -1;
+	}
+	if ((m1->toFile - 1 >= 0) && gs->board[m1->toFile - 1][4] == W_PAWN) {
+	  gs->ep_possible[0][m1->toFile - 1] = 1;
+	}
+      }
+    }
+  }
+  /************** and here's the end **************/
+  return MOVE_OK;
+}
+
+
+
+