item_def *find_floor_item(object_class_type cls, int sub_type);

bool copy_item_to_grid( const item_def &item, int x_plos, int y_plos, 

bool copy_item_to_grid( const item_def &item, int x_plos, int y_plos,

}
item_def *find_floor_item(object_class_type cls, int sub_type)
{
    int item = NON_ITEM;
    for (int y = 0; y < GYM; ++y)
        for (int x = 0; x < GXM; ++x)
        {
            item = igrd[x][y];
            while (item != NON_ITEM)
            {
                item_def &i(mitm[item]);
                if (is_valid_item(i) && i.base_type == cls
                    && i.sub_type == sub_type)
                    return (&i);
                item = i.link;
            }
        }
    return (NULL);

    mpr("generate_abyss().", MSGCH_DIAGNOSTICS);

    mprf(MSGCH_DIAGNOSTICS,
         "generate_abyss(); turn_on_level: %d", env.turns_on_level);

// Returns the roll to use to check if we want to create an abyssal rune.
static int _abyssal_rune_roll()
{
    if (you.attribute[ATTR_ABYSSAL_RUNES])
        return (-1);
    // The longer the player's hung around in the Abyss, the more
    // likely the rune. Never generate a new rune if the player
    // already found one, but make the Abyssal rune eligible for
    // generation again if the player loses it.
    // If the player leaves the Abyss turns_on_level resets to 0. So
    // hang in there if you want your Abyssal rune fix quick. :P
    // Worshippers of Lugonu with decent piety will attract the rune
    // to themselves.
    const bool lugonu_favoured =
        (you.religion == GOD_LUGONU && !player_under_penance()
         && you.piety > 120);
    const int cutoff = lugonu_favoured ? 50 : 500;
    const int scale = lugonu_favoured ? 10 : 40;
    const int odds =
        std::max(200 - std::max((env.turns_on_level - cutoff) / scale, 0), 6);
#ifdef DEBUG_ABYSS
    mprf(MSGCH_DIAGNOSTICS, "Abyssal rune odds: 1 in %d", odds);
#endif
    return (odds);
}

    // Any rune on the floor prevents the abyssal rune from being generated.
    bool placed_abyssal_rune =
        find_floor_item(OBJ_MISCELLANY, MISC_RUNE_OF_ZOT);

    mpr("generate_area().", MSGCH_DIAGNOSTICS);

    mprf(MSGCH_DIAGNOSTICS,
         "generate_area(). turns_on_level: %d, rune_on_floor: %s",
         env.turns_on_level, placed_abyssal_rune? "yes" : "no");

    const int abyssal_rune_roll = _abyssal_rune_roll();

                    if (one_chance_in(200))

                    if (!placed_abyssal_rune && abyssal_rune_roll != -1
                        && one_chance_in(abyssal_rune_roll))

                        placed_abyssal_rune = true;

            // HACK: Why doesn't is_terrain_known() work here?

            // is_terrain_known() doesn't work on unmappable levels because
            // mapping flags are not set on such levels.

    generate_area(5, 5, (GXM - 5), (GYM - 5));

    generate_area(MAPGEN_BORDER, MAPGEN_BORDER,
                  GXM - MAPGEN_BORDER, GYM - MAPGEN_BORDER);

    generate_area( 10, 10, (GXM - 10), (GYM - 10) );

    generate_area(MAPGEN_BORDER, MAPGEN_BORDER,
                  GXM - MAPGEN_BORDER, GYM - MAPGEN_BORDER);