diff --git a/include/dungeon/dungeon.h b/include/dungeon/dungeon.h
index 2b92c96..f8214fd 100644
--- a/include/dungeon/dungeon.h
+++ b/include/dungeon/dungeon.h
@@ -73,6 +73,7 @@ bool dungeon_load(struct dungeon_context *ctx, int num);
 void dungeon_set_camera(int surface, float x, float y, float z, float angle, float angle_p);
 void dungeon_set_walked(int surface, int x, int y, int z, int flag);
 int dungeon_get_walked(int surface, int x, int y, int z);
+void dungeon_set_walked_all(int surface);
 int dungeon_calc_conquer(int surface);
 bool dungeon_load_walk_data(int surface, int map, struct page **page);
 bool dungeon_save_walk_data(int surface, int map, struct page **page);
diff --git a/src/dungeon/dungeon.c b/src/dungeon/dungeon.c
index 54e7888..7063b45 100644
--- a/src/dungeon/dungeon.c
+++ b/src/dungeon/dungeon.c
@@ -326,6 +326,18 @@ void dungeon_set_walked(int surface, int x, int y, int z, int flag)
 	}
 }
 
+void dungeon_set_walked_all(int surface)
+{
+	struct dungeon_context *ctx = dungeon_get_context(surface);
+	if (!ctx)
+		return;
+	int nr_cells = dgn_nr_cells(ctx->dgn);
+	for (struct dgn_cell *c = ctx->dgn->cells; c < ctx->dgn->cells + nr_cells; c++) {
+		c->walked = 1;
+		dungeon_map_reveal(ctx, c->x, c->y, c->z, false);
+	}
+}
+
 int dungeon_get_walked(int surface, int x, int y, int z)
 {
 	struct dungeon_context *ctx = dungeon_get_context(surface);
diff --git a/src/hll/DrawDungeon.c b/src/hll/DrawDungeon.c
index 2c4a5e1..e48211f 100644
--- a/src/hll/DrawDungeon.c
+++ b/src/hll/DrawDungeon.c
@@ -255,7 +255,6 @@ CELL_SETTER(DrawDungeon_SetTexDoorE, int, cell->east_door, true);
 
 HLL_QUIET_UNIMPLEMENTED( , void, DrawDungeon, SetDrawHalfFlag, int surface, int flag);
 HLL_QUIET_UNIMPLEMENTED(0, int,  DrawDungeon, GetDrawHalfFlag, int surface);
-//void DrawDungeon_SetWalkedAll(int surface);
 //int DrawDungeon_CalcNumofFloor(int surface);
 //int DrawDungeon_CalcNumofWalk(int surface);
 //int DrawDungeon_CalcNumofWalk2(int surface);
@@ -384,7 +383,7 @@ HLL_QUIET_UNIMPLEMENTED( , void, DrawDungeon, RestartTimer, void);
 	HLL_EXPORT(SetDrawHalfFlag, DrawDungeon_SetDrawHalfFlag), \
 	HLL_EXPORT(GetDrawHalfFlag, DrawDungeon_GetDrawHalfFlag), \
 	HLL_EXPORT(SetWalked, dungeon_set_walked), \
-	HLL_TODO_EXPORT(SetWalkedAll, DrawDungeon_SetWalkedAll), \
+	HLL_EXPORT(SetWalkedAll, dungeon_set_walked_all), \
 	HLL_TODO_EXPORT(CalcNumofFloor, DrawDungeon_CalcNumofFloor), \
 	HLL_TODO_EXPORT(CalcNumofWalk, DrawDungeon_CalcNumofWalk), \
 	HLL_TODO_EXPORT(CalcNumofWalk2, DrawDungeon_CalcNumofWalk2), \