Pokémon Gold and Silver:Notes
The map header is split in a few different parts, linked to by pointers :
1 byte - Bank of second part 1 byte - Tileset ID 1 byte - Permission (?) 2 bytes - Pointer to secondary header (little-endian) 1 byte - Location ID 1 byte - Music ID 1 byte - Upper nibble = 1 if no phone signal Lower nibble = Day/Night-type palette 1 byte - Fishing group
1 byte - ID of block displayed "outside" of map 1 byte - Map height 1 byte - Map width 1 byte - Bank of block data 2 bytes - Pointer to block data (little-endian) 1 byte - Bank of scripts and events headers 2 bytes - Pointer to scripts header 2 bytes - Pointer to events header 1 byte - Bitfield of which map connections are enabled Bits : 0 - 0 - 0 - 0 - NORTH - SOUTH - WEST - EAST
Map connections allow going from map A to map B simply by walking ; example : New Bark Town and Route 29 are connected through this mechanism.
Map connections are placed right after the secondary header, in this order : NORTH -> SOUTH -> WEST -> EAST (of current map).
A connection not enabled (bit not set in secondary header) is simply omitted. There can be none (example : all "interior" maps).
1 byte - Connected map group 1 byte - Connected map ID 2 bytes - Pointer to top-left block of map connection 2 bytes - Destination pointer (in the OverworldMap buffer) (?) 1 byte - Length of the connection 1 byte - Connected map's width 1 byte - Top-left block of connection, vertical coordinate within target map (?) 1 byte - Top-left block of connection, horizontal coordinate within target map (?) 2 bytes - Pointer to "window" (?)
1 byte - Number of map triggers (Then follow as many map triggers as specified) 1 byte - Number of map callbacks (Then follow as many map callbacks as specified)
What does this do ?
Structure : NULL-terminated list of pointers
What does this do ?
Structure : Type ? (1 byte), then pointer to script (2 bytes)
Wild Pokémon data isn't stored in the map's header. Instead, the game has 7 tables.
|Table||Gold/Silver location||Crystal location|
|??? | 92488|
|??? | 2A5E9|
|??? | 2B274|
|??? | 2B11D|
|??? | 2B7F7|
|??? | 2B8D0|
|??? | 2B92F|
Structure of an entry :
1 byte - Map group 1 byte - Map ID 1 byte - Encounter rate at morning 1 byte - Encounter rate at day 1 byte - Encounter rate at night Repeated 7 times : 1 byte - Level of Pokémon, encountered at morning 1 byte - Species of Pokémon, encountered at morning Repeated 7 times : 1 byte - Level of Pokémon, encountered at day 1 byte - Species of Pokémon, encountered at day Repeated 7 times : 1 byte - Level of Pokémon, encountered at night 1 byte - Species of Pokémon, encountered at night
The list is $FF-terminated. Maps where the encounter rates and encountered Pokémon don't depend on the time simply duplicate entries.
When RNG decides it's time for an encounter, the game browses the table. If it finds an entry that begins with the map's group and ID, it performs a RNG check against the corresponding encounter rate.
If the check passes, the game picks an encounter in the corresponding table.
The game picks one table depending on the map's fishing group and the Rod used.
Then what does it do ?
Johto or Kanto ?
The game decides depending on the map's location in the Pokégear map
Obtain map's location If location is S.S. Aqua Map is in Johto End If location is "Special map" (example : Pokémon Center 2F, which are all the same map) Consider location of previous map instead End If location <= $2E ($2E = Silver Cave, $2F = Pallet Town) Map is in Johto Else If location == $58 (Victory Road) Map is in Johto Else Map is in Kanto End End
ID Battle Type -- ----------- 00 Normal 01 02 No Pokémon (guaranteed escape) 03 Tutorial battle 04 Hooked Pokémon 05 Suicune 06 Bug catching contest 07 Shiny Gyarados (14 ATK / 10 DEF / 10 SPEED / 10 SPC) 08 Headbutt 09 0A 0B 0C Entei, Raikou
|Internal Data for Pokémon Gold and Silver|