Author
But when I figured it out, I got the format!
Every third address is actually not a type, but an indicator of "Super Effective", "Not Very Effective", or "No Effect."
Essentially, Fire = Super effective, Rock = Not Very Effective, and Normal = No Effect.
So the first three addresses read: "Water" against "Fire" is "Super Effective"
note that the table below has "ground" and "rock" mixed up, so that "Ground" = "Not Very Effective"
------------------------------------------------------
Original Post
I have been trying to find and edit the type match-up table from Pokemon Red, that is, where it is defined that water is super-effective against fire and electric has no effect against ground.
After looking through all of the Pokemon Red and Blue related Docs, Utilities, and ROM Hacks, I found the "Pokémon Red - Dark and Steel Types" patch by Koolboyman. I figured that it would have to access the addresses where the type match-up table is stored. I applied to patch to a Pokemon Red ROM, and used a python script to determine the differences in the ROM, before and after.
In doing so I found a range of addresses that were altered. Moreover, the values stored in these addresses are all references to various Pokemon types. (I found the Pokemon type references by analyzing the Pokemon Stats section of the ROM, according to "Giegue's Master Guide to Hacking Pokemons Games Red-Crystal")
The problem now is that I do not know how to interpret the table, and so I am asking for help. If anyone has done this sort of hack before and still has their notes, or can decipher the format of the table below, please let me know!
Here is the type matchup table taken from a clean Pokemon Red ROM:
[addr in hex][addr in dec] : Value
[3e474][255092] : Water
[3e475][255093] : Fire
[3e476][255094] : Fire
[3e477][255095] : Fire
[3e478][255096] : Grass
[3e479][255097] : Fire
[3e47a][255098] : Fire
[3e47b][255099] : Ice
[3e47c][255100] : Fire
[3e47d][255101] : Grass
[3e47e][255102] : Water
[3e47f][255103] : Fire
[3e480][255104] : Electric
[3e481][255105] : Water
[3e482][255106] : Fire
[3e483][255107] : Water
[3e484][255108] : Ground
[3e485][255109] : Fire
[3e486][255110] : Rock
[3e487][255111] : Flying
[3e488][255112] : Normal
[3e489][255113] : Water
[3e48a][255114] : Water
[3e48b][255115] : Ground
[3e48c][255116] : Fire
[3e48d][255117] : Fire
[3e48e][255118] : Ground
[3e48f][255119] : Electric
[3e490][255120] : Electric
[3e491][255121] : Ground
[3e492][255122] : Ice
[3e493][255123] : Ice
[3e494][255124] : Ground
[3e495][255125] : Grass
[3e496][255126] : Grass
[3e497][255127] : Ground
[3e498][255128] : Psychic
[3e499][255129] : Psychic
[3e49a][255130] : Ground
[3e49b][255131] : Fire
[3e49c][255132] : Water
[3e49d][255133] : Ground
[3e49e][255134] : Grass
[3e49f][255135] : Fire
[3e4a0][255136] : Ground
[3e4a1][255137] : Water
[3e4a2][255138] : Grass
[3e4a3][255139] : Ground
[3e4a4][255140] : Electric
[3e4a5][255141] : Grass
[3e4a6][255142] : Ground
[3e4a7][255143] : Normal
[3e4a8][255144] : Ground
[3e4a9][255145] : Ground
[3e4aa][255146] : Normal
[3e4ab][255147] : Ghost
[3e4ac][255148] : Normal
[3e4ad][255149] : Ghost
[3e4ae][255150] : Ghost
[3e4af][255151] : Fire
[3e4b0][255152] : Fire
[3e4b1][255153] : Bug
[3e4b2][255154] : Fire
[3e4b3][255155] : Fire
[3e4b4][255156] : Ground
[3e4b5][255157] : Ground
[3e4b6][255158] : Water
[3e4b7][255159] : Rock
[3e4b8][255160] : Fire
[3e4b9][255161] : Electric
[3e4ba][255162] : Rock
[3e4bb][255163] : Normal
[3e4bc][255164] : Electric
[3e4bd][255165] : Flying
[3e4be][255166] : Fire
[3e4bf][255167] : Grass
[3e4c0][255168] : Rock
[3e4c1][255169] : Fire
[3e4c2][255170] : Grass
[3e4c3][255171] : Bug
[3e4c4][255172] : Ground
[3e4c5][255173] : Grass
[3e4c6][255174] : Poison
[3e4c7][255175] : Ground
[3e4c8][255176] : Grass
[3e4c9][255177] : Ground
[3e4ca][255178] : Fire
[3e4cb][255179] : Grass
[3e4cc][255180] : Flying
[3e4cd][255181] : Ground
[3e4ce][255182] : Ice
[3e4cf][255183] : Water
[3e4d0][255184] : Ground
[3e4d1][255185] : Ice
[3e4d2][255186] : Grass
[3e4d3][255187] : Fire
[3e4d4][255188] : Ice
[3e4d5][255189] : Rock
[3e4d6][255190] : Fire
[3e4d7][255191] : Ice
[3e4d8][255192] : Flying
[3e4d9][255193] : Fire
[3e4da][255194] : Fighting
[3e4db][255195] : Normal
[3e4dc][255196] : Fire
[3e4dd][255197] : Fighting
[3e4de][255198] : Poison
[3e4df][255199] : Ground
[3e4e0][255200] : Fighting
[3e4e1][255201] : Flying
[3e4e2][255202] : Ground
[3e4e3][255203] : Fighting
[3e4e4][255204] : Psychic
[3e4e5][255205] : Ground
[3e4e6][255206] : Fighting
[3e4e7][255207] : Bug
[3e4e8][255208] : Ground
[3e4e9][255209] : Fighting
[3e4ea][255210] : Ground
[3e4eb][255211] : Fire
[3e4ec][255212] : Fighting
[3e4ed][255213] : Ice
[3e4ee][255214] : Fire
[3e4ef][255215] : Fighting
[3e4f0][255216] : Ghost
[3e4f1][255217] : Normal
[3e4f2][255218] : Poison
[3e4f3][255219] : Grass
[3e4f4][255220] : Fire
[3e4f5][255221] : Poison
[3e4f6][255222] : Poison
[3e4f7][255223] : Ground
[3e4f8][255224] : Poison
[3e4f9][255225] : Rock
[3e4fa][255226] : Ground
[3e4fb][255227] : Poison
[3e4fc][255228] : Bug
[3e4fd][255229] : Fire
[3e4fe][255230] : Poison
[3e4ff][255231] : Ground
[3e500][255232] : Ground
[3e501][255233] : Poison
[3e502][255234] : Ghost
[3e503][255235] : Ground
[3e504][255236] : Rock
[3e505][255237] : Fire
[3e506][255238] : Fire
[3e507][255239] : Rock
[3e508][255240] : Electric
[3e509][255241] : Fire
[3e50a][255242] : Rock
[3e50b][255243] : Grass
[3e50c][255244] : Ground
[3e50d][255245] : Rock
[3e50e][255246] : Bug
[3e50f][255247] : Ground
[3e510][255248] : Rock
[3e511][255249] : Ground
[3e512][255250] : Fire
[3e513][255251] : Rock
[3e514][255252] : Poison
[3e515][255253] : Fire
[3e516][255254] : Flying
[3e517][255255] : Electric
[3e518][255256] : Ground
[3e519][255257] : Flying
[3e51a][255258] : Fighting
[3e51b][255259] : Fire
[3e51c][255260] : Flying
[3e51d][255261] : Bug
[3e51e][255262] : Fire
[3e51f][255263] : Flying
[3e520][255264] : Grass
[3e521][255265] : Fire
[3e522][255266] : Flying
[3e523][255267] : Ground
[3e524][255268] : Ground
[3e525][255269] : Psychic
[3e526][255270] : Fighting
[3e527][255271] : Fire
[3e528][255272] : Psychic
[3e529][255273] : Poison
[3e52a][255274] : Fire
[3e52b][255275] : Bug
[3e52c][255276] : Fire
[3e52d][255277] : Ground
[3e52e][255278] : Bug
[3e52f][255279] : Grass
[3e530][255280] : Fire
[3e531][255281] : Bug
[3e532][255282] : Fighting
[3e533][255283] : Ground
[3e534][255284] : Bug
[3e535][255285] : Flying
[3e536][255286] : Ground
[3e537][255287] : Bug
[3e538][255288] : Psychic
[3e539][255289] : Fire
[3e53a][255290] : Bug
[3e53b][255291] : Ghost
[3e53c][255292] : Ground
[3e53d][255293] : Bug
[3e53e][255294] : Poison
[3e53f][255295] : Fire
[3e540][255296] : Ground
[3e541][255297] : Fire
[3e542][255298] : Fire
[3e543][255299] : Ground
[3e544][255300] : Fighting
[3e545][255301] : Ground
[3e546][255302] : Ground
[3e547][255303] : Rock
[3e548][255304] : Ground
[3e549][255305] : Ground
[3e54a][255306] : Flying
[3e54b][255307] : Fire
[3e54c][255308] : Ground
[3e54d][255309] : Bug
[3e54e][255310] : Fire
[3e54f][255311] : Ground
[3e550][255312] : Ice
[3e551][255313] : Fire
[3e552][255314] : Ghost
[3e553][255315] : Normal
[3e554][255316] : Normal
[3e555][255317] : Ghost
[3e556][255318] : Psychic
[3e557][255319] : Normal
[3e558][255320] : Fire
[3e559][255321] : Dragon
[3e55a][255322] : Ground
[3e55b][255323] : Water
[3e55c][255324] : Dragon
[3e55d][255325] : Ground
[3e55e][255326] : Electric
[3e55f][255327] : Dragon
[3e560][255328] : Ground
[3e561][255329] : Grass
[3e562][255330] : Dragon
[3e563][255331] : Ground
[3e564][255332] : Ice
[3e565][255333] : Dragon
[3e566][255334] : Fire
[3e567][255335] : Dragon
[3e568][255336] : Dragon
[3e569][255337] : Fire
[3e56a][255338] : END OF TABLE
Here is the table I used to determine the Types
00 = Normal
01 = Fighting
02 = Flying
03 = Poison
04 = Rock
05 = Ground
07 = Bug
08 = Ghost
14 = Fire
15 = Water
16 = Grass
17 = Electric
18 = Psychic
19 = Ice
1A = Dragon