#+title: Notes on Deconstructing Pokemon Yellow

 #+author: Dylan Holmes

 #+email: rlm@mit.edu

 #+description:

 #+keywords:

 #+SETUPFILE: ../../aurellem/org/setup.org

 #+INCLUDE: ../../aurellem/org/level-0.org

 #+BABEL: :exports both :noweb yes :cache no :mkdirp yes

 

 

 # pokedollar: U+20B1

 * Mapping the ROM

 

 | ROM address (hex) | Description     | Format          | Example         |

 |-------------------+-----------------+-----------------+-----------------|

 |                   | <15>            | <15>            | <15>            |

 | 0233C-            | Shop inventories. |                 |                 |

 | 04495-            | Prices of items. | Each price is two bytes of binary-coded decimal. Prices are separated by zeroes. Priceless items[fn::Like the Pok\eacute{}dex and other unsellable items.] are given a price of zero. | The cost of lemonade is 0x03 0x50, which translates to a price of ₱350. |

 | 045B7-0491E       | Names of the items in memory. | Variable-length item names (strings of character codes). Names are separated by a single 0x80 character. | MASTER BALL#ULTRA BALL#... |

 | 04D89-            | Lists of wild Pok\eacute{}mon to encounter in each region. | Each list contains ten Pokemon (ids) and their levels; twenty bytes in total. First, the level of the first Pokemon. Then the internal id of the first Pokemon. Next, the level of the second Pokemon, and so on. Since Pokemon cannot have level 0, the lists are separated by a pair 0 /X/, where /X/ is an apparently random Pokemon id. | The first list is (3 36 4 36 2 165 3 165 2 36 3 36 5 36 4 165 6 36 7 36 0 25), i.e. level 3 pidgey, level 4 pidgey, level 2 rattata, level 3 rattata, level 2 pidgey, level 3 pidgey, level 5 pidgey, level 4 rattata, level 6 pidgey, level 7 pidgey, level 0 end-of-list. |

 | 05EDB.            | Which Pok\eacute{}mon to show during Prof. Oak's introduction. | A single byte, the Pok\eacute{}mon's internal id. | In Pok\eacute{}mon Yellow, it shows Pikachu during the introduction; Pikachu's internal id is 0x54. |

 | 06698-            | ? Background music. |                 |                 |

 | 0822E-082F?       | Pointers to background music, part I. |                 |                 |

 | 0CB95-            | Pointers to lists of wild pokemon to encounter in each region. These lists begin at 04D89, see above. | Each pointer is a low-byte, high-byte pair. | The first entry is 0x89 0x4D, corresponding to the address 0x4D89, the location of the first list of wild Pok\eacute{}mon (see above). |

 | 1232D-            | Which moves are taught by the TMs and HMs |                 |                 |

 | 27D99-27DFF       | Names of the Pok\eacute{}mon types. | Variable-length type names (strings of character codes). Names are separated by a single 0x80 character. | NORMAL#FIGHTING#... |

 | 27E77-            | Trainer title names. |                 | YOUNGSTER#BUG CATCHER#LASS#... |

 | 34000-            | Evolution and learnset data. |                 |                 |

 | 38000-            | The basic properties and effects of moves. | Fixed-length (6 byte) continguous descriptions (no separating character): move-index, move-effect, power, move-type, accuracy, pp. | The entry for Pound, the first attack in the list, is (1 0 40 0 255 35). See below for more explanation. |

 | 383DE-            | Species data for the Pokemon, listed in Pokedex order: Pokedex number; base moves; types; learnable TMs and HMs; base HP, attack, defense, speed, special; sprite data. |                 |                 |

 | 39462-            | The Pok\eacute{}mon cry data. | Fixed-length (3 byte) descriptions of cries. |                 |

 | 3B1E5-            | Pointers to evolution/learnset data. |                 |                 |

 | 40687-            | Species data from the Pok\eacute{}dex: species name, height, weight, etc. | Fixed-length sequences of bytes. See below for specifics. |                 |

 | 410B1-            | A conversion table between internal order and Pokedex order. |                 |                 |

 | 71500-            | Names of places. |                 |                 |

 | 7C249-7C2??       | Pointers to background music, pt II. |                 |                 |

 | 98000-            | Dialogue        |                 |                 |

 | B8000-            | The text of each Pokemon's Pok\eacute{}dex entry. |                 |                 |

 | BC000-            | Move names.     |                 |                 |

 | E8000-E876C       | Names of the \ldquo{}190\rdquo{} species of Pok\eacute{}mon in memory. | Fixed length (10-letter) Pok\eacute{}mon names. Any extra space is padded with the character 0x80. The names are in \ldquo{}internal order\rdquo{}. | RHYDON####KANGASKHANNIDORAN♂#... |

 |                   |                 |                 |                 |

 |                   |                 |                 |                 |

 

 * Appendices

 ** Internal Pok\eacute{}mon IDs

 ** Type IDs

 ** Basic effects of moves

 ** Alphabet code