Etrian Odyssey 3 Drowned City: Making cheat codes, questions on RAM + share what's done so far

Discussion in 'NDS - ROM Hacking and Translations' started by demonata, Nov 15, 2015.

  1. demonata
    OP

    demonata Member

    Newcomer
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    Sep 26, 2010
    Hong Kong
    Just noticed that no$gba debugger is free already, so I picked it up and try to do something I wanted to.
    There are quite a few codes for the JP version that changes game mechanics instead of in-game values,
    and making the US version is my target.

    So far my first US code is working great:
    1st skill of a class is not restricted to main class anymore (can be selected in subclass skill list)
    020A6C84 E1A00000

    Now I'm working on my 2nd one, and needs some advice:
    I want to create a code in US version like this one,
    (JP version) item sell price multiplier (XX=03 will become 3 times)
    020001E0 E3A040XX
    020001E4 E0000490
    020001E8 E8BD8010
    020B5BE4 EAFD297D

    I looked into the JP-ver. memory to see what these addresses are...
    For the first 3 lines (also showing 1 line above/below here),
    I have no idea what these are, and so far I cannot trigger break point on them, or find similar pattern in US version.
    020001DC 64234507 strvst r4,[r3],-507h
    020001E0 DE42641A movle p4,2,c2,c10,0,r6
    020001E4 3A7A759F bcc 3E9D868h
    020001E8 8ABAFD00 bhi 0EBF5F0h
    020001EC BA392F23 blt 2E4BE80h

    For the last address 020B5BE4, I found that it's part of the logic that runs when I 1st enter sell items menu
    020B5BCC E5900008 ldr r0,[r0,8h]
    020B5BD0 EBFD8A25 bl 201846Ch
    020B5BD4 E1A01000 mov r1, r0
    020B5BD8 E59F0014 ldr r0,=3ECCCCCDh
    020B5BDC EBFD8A34 bl 20184B4h
    020B5BE0 EBFD89F2 bl 20183B0h
    020B5BE4 E8BD8010 pop r4,r15

    After applying the JP code to JP-ver. of game, basically 020B5BE4 routes to the above 3,
    which do the inflation math and the original pop instruction.
    020001E0 E3A04003 mov r4,3h<=multiply by 3 as example
    020001E4 E0000490 mul r0,r0,r4
    020001E8 E8BD8010 pop r4,r15
    020B5BE4 EAFD297D b 20001E0h

    For US version, I'm able to locate the same set of logic running when I enter sell menu, location:
    020B0458 E8BD8010 pop r4,r15

    But for the first 3 lines, I really don't know what to do with them....
    Are these address safe to be overwritten by this code (i.e. useless address???)

    FYI I have zero knowledge about assembly level programming :)
    ++If there is a better place to ask about these, please let me know what forum it is, thx
     
    Last edited by demonata, Nov 15, 2015
  2. AsPika2219

    AsPika2219 Pikachu going beach!

    Member
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    Jun 17, 2010
    Malaysia
    Cats City
    Nice codes! :lol: Plus, post your working codes at Game Hacking website here! Register first and enjoy your codes! :) :yaynds:

    http://gamehacking.org/vb/