Pokémon data structure (Generation I): Difference between revisions

 

The '''Pokémon data structure''' in the [[Generation I]] games stores most information about the current state of a {{player}}'s [[caught Pokémon]]. It has a length of 44 bytes for Pokémon in the player's [[party]] and 33 bytes for Pokémon in boxes on [[Bill's PC]]. The information lost when depositing a Pokémon in Bill's PC is its [[level]] and its {{stat|HP}}, {{stat|Attack}}, {{stat|Defense}}, {{stat|Special}} and {{stat|Speed}}; this allows the [[box trick]] to work by recalculating the lost information upon withdrawing the Pokémon again.

| 0x00 || [[List of Pokémon by index number (GB)|Index number of species]] || Byte

| 0x01 || Remaining HP || {{tt|Word|2 bytes, with Remaining HP / 256 stored first}}

| 0x03 || Level? || Byte

| 0x04 || [[Status ailment]]s || Byte

| 0x05 || [[Elemental type|Type 1]] || Byte

| 0x06 || Type 2 || Byte

| 0x07 || [[Catch rate]]/[[Held item]] || Byte

| 0x08 || [[List of moves#Generation I|Index number of first move]] || Byte

| 0x09 || Index number of second move || Byte

| 0x0A || Index number of third move || Byte

| 0x0B || Index number of fourth move || Byte

| 0x0C || [[Trainer ID number|Original Trainer ID number]] || {{tt|Word|2 bytes, with Trainer ID number / 256 stored first}}

| 0x0E || [[Experience]] || {{tt|3 bytes|Experience / 65536, then Experience / 256 mod 256, then Experience mod 256}}

| 0x11 || {{stat|HP}} [[stat experience]] || {{tt|Word|2 bytes, with HP stat experience / 256 stored first}}

| 0x13 || {{stat|Attack}} stat experience || {{tt|Word|2 bytes, with Attack stat experience / 256 stored first}}

| 0x15 || {{stat|Defense}} stat experience || {{tt|Word|2 bytes, with Defense stat experience / 256 stored first}}

| 0x17 || {{stat|Speed}} stat experience || {{tt|Word|2 bytes, with Speed stat experience / 256 stored first}}

| 0x19 || {{stat|Special statistic|Special}} stat experience || {{tt|Word|2 bytes, with Special stat experience / 256 stored first}}

| 0x1B || [[Individual values]] || {{tt|Word|4 bits for each IV excluding HP}}

| 0x1D || {{PP}} of first move || {{tt|Byte|6 bits for current PP, 2 bits for applied PP Ups}}

| 0x1E || {{PP}} of second move || {{tt|Byte|6 bits for current PP, 2 bits for applied PP Ups}}

| 0x1F || {{PP}} of third move || {{tt|Byte|6 bits for current PP, 2 bits for applied PP Ups}}

| 0x20 || {{PP}} of fourth move || {{tt|Byte|6 bits for current PP, 2 bits for applied PP Ups}}

| 0x21 || [[Level]] || Byte

| 0x22 || Maximum HP || {{tt|Word|2 bytes, with Maximum HP / 256 stored first}}

| 0x24 || Attack || {{tt|Word|2 bytes, with Maximum HP / 256 stored first}}

| 0x26 || Defense || {{tt|Word|2 bytes, with Maximum HP / 256 stored first}}

| 0x28 || Speed || {{tt|Word|2 bytes, with Maximum HP / 256 stored first}}

| 0x2A || Special || {{tt|Word|2 bytes, with Maximum HP / 256 stored first}}

Notably missing from this structure are the Pokémon's nickname and the original Trainer's name, which are stored elsewhere. In Pokemon Blue (US), this structure appears to

The [[List of Pokémon by index number (GB)|index number]] for the Pokémon's species.

===Status ailments===

The [[status ailment]]s of the Pokémon, as a bit field.

! style="text-align: center; background: #ccf;" | '''Status ailment'''

Since being [[Status ailment#Badly poisoned|badly poisoned]] is a temporary condition in [[Pokémon battle|battles]], it is not stored here. Confusion is also not stored here. 0x00 means that the Pokémon is not affected by any major status ailment.

The [[elemental type]] of the Pokémon. If the Pokémon has only one type, both values are the same. It seems redundant, as there is no way a Pokémon can change type in Generation I besides [[Evolution|evolving]], and through the use of Conversion.

 

If a Pokémon has only one type, the byte for the second type will match that of the first one.

When trading with {{3v2|Gold|Silver|Crystal}}, this field is co-opted for storing the Pokémon's [[held item]].

The following are ROM offsets for the beginning of the party structure while walking around:

* Red (en): Unknown

* Yellow (en): Unknown

====6-Pokemon Party Structure====

| 0x00 || Number of Pokemon in party || 1 Byte

| 0x01 || List Party Pokemon Index values || 7 Bytes

| 0x08 || 1st Pokemon structure || 44 Bytes

| 0x34 || 2nd Pokemon structure || 44 Bytes

| 0x60 || 3rd Pokemon structure || 44 Bytes

| 0x8C || 4th Pokemon structure || 44 Bytes

| 0xB8 || 5th Pokemon structure || 44 Bytes

| 0xE4 || 6th Pokemon structure || 44 Bytes

| 0X110 || 4 0x000B's to terminate || 4 Words

The list of party index values ends with FF, which is followed by 00s through the rest of the section. The set of Pokemon structures themselves, on the other hand, are followed by a set of values whose significance are not yet clear.

Also of note is that the storage of the current Pokemon's information during battle. The internal index of the current is stored at 0xCF91, and the full Pokemon data structure begins at 0xCF98.

{{data structure}}