Map16 Low Byte Table. For horizontal levels, $1B0 tiles per screen, where each screen can be indexed using the format ------y yyyyxxxx. $7E:FE00-$7E:FFFF are unused. For vertical levels, $200 bytes per screen, with the format --sssssx yyyyxxxx. All bytes are used. If layer 2 or 3 is interactive in the level, it uses screens 10-1F (0E-1B in vertical levels).
On the overworld: $7E:C800-$7E:CFFF is used as the Layer 1 tilemap for the overworld. To index this table, use $7E:1F11, $7E:1F1F, and $7E:1F21 to find Mario, or use $7E:1F12, $7E:1F23, and $7E:1F25 to find Luigi. X position / 16: %---- ---- ---X xxxx Y position / 16: %---- ---- ---Y yyyy Index to this table: %---- -SYX yyyy xxxx * If Mario is on a submap, the S bit is set.
$7E000-$7E7FF is used as a table that contains the translevel numbers for every Layer 1 tile, in the format of $7E:13BF. $7E800-$7EFFF is used as a table that contains the path direction settings for every Layer 1 tile, in the format of $04678. $7E:E400-$7E:EBFF is used for uploading the Layer 1 tile map to VRAM in 2KB chunks. One chunk is uploaded per frame for four frames during transitions between the main overworld and submaps. Data is refreshed after each DMA.