Index: class.doc
==================================================================
--- class.doc
+++ class.doc
@@ -2114,11 +2114,14 @@
   stationary object, 1 if another object is trying to move into this
   stationary object, 2 if two objects are trying to move into the same
   space, or 3 if two or more objects forming a loop are trying to move
   into each other). There is no guarantee that this will only be called
   once; sometimes it will be called multiple times for a single collision
-  or for multiple collisions with the same objects. (TODO)
+  or for multiple collisions with the same objects. The return value has
+  bit0 to allow the move, bit1 to handle sharpness, and bit2 to retry if
+  the move fails. The bit16 and higher bits will have the similar effect
+  for the other object instead.
 
 CONFLICT
   Called during scheduling of a deferred move if it is already currently
   scheduled to move but in a different direction. Arg1 is the direction
   that it is trying to schedule the move in. If the return value is false

Index: exec.c
==================================================================
--- exec.c
+++ exec.c
@@ -1201,16 +1201,19 @@
 
 static int defer_move(Uint32 obj,Uint32 dir,Uint8 plus) {
   Object*o;
   Object*q;
   Uint32 n;
+  Uint8 x,y;
   Value v;
   if(StackProtection()) Throw("Call stack overflow during movement");
   if(obj==VOIDLINK || obj==control_obj) return 0;
   o=objects[obj];
   if(o->oflags&(OF_DESTROYED|OF_BIZARRO)) return 0;
   dir=resolve_dir(obj,dir);
+  x=o->x+x_delta[dir]; y=o->y+y_delta[dir];
+  if(x<1 || x>pfwidth || y<1 || y>pfheight) return 0;
   if(plus) {
     if(o->oflags&OF_MOVING) {
       if(o->dir==dir) return 1;
       v=send_message(VOIDLINK,obj,MSG_CONFLICT,NVALUE(dir),NVALUE(0),NVALUE(0));
       if(!v_bool(v)) return 0;
@@ -1220,14 +1223,14 @@
   } else {
     if(!(o->oflags&OF_MOVING)) return 0;
     if(o->dir!=dir) return 0;
     o->oflags&=~OF_MOVING;
   }
-  n=playfield[o->x+o->y*64-65];
+  n=playfield[x+y*64-65];
   while(n!=VOIDLINK) {
     q=objects[n];
-    if(!(q->oflags&(OF_DESTROYED|OF_VISUALONLY)) && ((q->height>0 && q->height>=o->climb) || (classes[q->class]->collisionLayers&classes[o->class]->collisionLayers))) {
+    if(!(q->oflags&(OF_DESTROYED|OF_VISUALONLY|OF_MOVING)) && ((q->height>0 && q->height>=o->climb) || (classes[q->class]->collisionLayers&classes[o->class]->collisionLayers))) {
       v=send_message(obj,n,MSG_BLOCKED,NVALUE(o->x),NVALUE(o->y),NVALUE(plus));
       if(v.t) Throw("Type mismatch");
       if(v.u&1) o->oflags&=~OF_MOVING;
       if(v.u&2) break;
     }
@@ -3051,11 +3054,11 @@
         }
       }
       objE=oE->up;
     }
   }
-  return ~h;
+  return h;
 }
 
 static void do_deferred_moves(void) {
   Object*o;
   Object*p;
@@ -3079,12 +3082,11 @@
           o->oflags=(o->oflags|OF_MOVED)&~OF_MOVING;
           i-=65;
           if(i<0) i=0;
           goto retry;
         }
-        stop:
-        if((h&5)!=4) o->oflags&=~OF_MOVING;
+        if((h&5)!=4) stop: o->oflags&=~OF_MOVING;
       }
       skip:
       n=o->up;
     }
   }