Table of Contents

• Static Code Analysis
• Quick Function Key
• Triggering the in-game DEBUG MODE

Static Code Analysis

We’ve found some functions key in determining how the game works.

• FUN_80020170
  • the game’s decompress function for files.
• FUN_8007d334
  • used to load a rectangle for an image to be drawn in.
  • The actual function to load an image, that uses this, is insub_8007d578.
• FUN_8001bad8
  • used to draw Japanese characters from the main text box Overlay.
• FUN_8001bc9c for English/ASCII characters (such as enemy names in the top right)
• sub_8001F57C
  • utilizes DAT_800E0190 which holds an array of 6 elements, which is populated by the file to handle/track to every BIN file.
• sub_8001F57C looks up a blob/Overlay part from one of those 6 BIN files, by a size-offset pair, and return a pointer to that blob.
  • then receives the index to the BIN file it should take the blob from (which is indirectly clamped by sub_8001E12C due to it loading 6 files)
  • And the sizeOffsetPair is size in the lower 0x1FFFF bits, shifted right by 2. And the top 0x7FFF bits are the offset into the BIN file.
  • it can be assumed that there ISN’T necessarily a global lookup table to all the blobs in the BIN files, but the game might just hardcode the offset and sizes where it needs it.
  • Need to find all the references to sub_8001F57C, collect the size offset pairs, and later patch them, if any of the blobs changed in size or offset. Maybe by a script or something.
• sub_8001E208 is used to load the blobs from OVR.BIN
  • Used this to confirm that the table in OVR.BIN encapsulates the whole file.
  • there seems to be a hard cap for 0x3F sectors in OVR.BIN
• sub_8001e504 loads textures with magic identifier TEX from either CHR.BIN or MAP.BIN.
  • these textures type may only be in those two BIN files.

Quick Function Key

• FUN_80020170 = decompress
• FUN_8007d2cc = DrawSync
• FUN_8007d234 = SetDispMask
• FUN_8007cf50 = ResetGraph
• FUN_8007d0c4 = SetGraphDebug
• FUN_8007d334 = StoreImage
• FUN_8007d7b8 = ClearOTagR
• FUN_8007d1d4 = DrawSyncCallback
• FUN_8001f74c = SystemError
• FUN_800872a4 = GetVideoMode
• FUN_800976f0 = SpuVoiceAttr
• FUN_8009b830 = SpuVolume
• FUN_80099480 = SpuInitHot
• FUN_8007ba20 = SetGeomOffset
• FUN_8007ba40 = SetGeomScreen
• FUN_8009d0c0 = SsSetStereo
• FUN_8001bc9c = GetCharacterData
• FUN_8001bad8 = DrawLargeCharacter
• FUN_8001d58c = DrawSmallCharacter
• FUN_8001cd14 = PrintText (Brightis Specific)
• FUN_8001cd34 = PrintTextBuffer (Brightis Specific)
• FUN_8001fb94 = LoadProgOverlay (Brightis Specific)
• FUN_801540b4 = RenderTextBuffer (Brightis Specific)
• FUN_80020014 = InitializeOnmOverlayTable (Brightis Specific)
• FUN_800200ac = InitializeOverlayTable (Brightis Specific)

Keep an eye on:

• FUN_8001bad8 - SJIS Controller(?)
• FUN_8001fb94 - Related to “Ovr Prog” (Prgressive Overlay)
• FUN_8001fd8c - Related to “CnstOvr” (Constant Overlay)
• FUN_8002a4b8 - Mentions of “DEMO PLAY” “DEMO REC” etc.

Triggering DEBUG MODE

• DAT_800aebea has to be 0x800 (or any value that has that bit set at least) (Part of Controler input?)
• DAT_800aec04 set to 0x20 (or any value that has this bit set)
• 0x801ffffc(in RAM) must be set to “DeV” or “PrV”

The game has verious checks to see if it’s in Debug. We’ve noticed there are various values it can be set to. All of these Debug modes seem to assume that “no CD (is) inserted.”

• 1: Best for testing and activating the debug mode (will not access Debug Menu 2)
• 2: Same as above with access to Debug Menu 2 options
• 4: Testing mode(?)
  • This runs into issues when loading the BIN files actually, if mode is > 2, it runs into not only into this trap, but also throws an error when it gets out of it.
  • 4 is also specially checked throughout the game, which might lead to different, non-desirable behaviour.
  • Maybe a mode to load files from an external drive or something?
• 8: proper debug mode. Makes frequent use of the hardware breakpoint 0x101 from which we don’t know how to recover from.
  TODO: Figure out how to get this working outside of Code Patching.