Last updated: October 14, 2026

ROM Map

How much of each bank of the cartridge is matched, and what lives where. Each tile below is one 64 KB bank: its fill is the share of that bank's code that is already matched, gold once the matched routines are verified too. Select a bank to jump to its slice map, where every 4 KB slice opens a list of the routines inside it.

How the cartridge is laid out

The US 1.0 cartridge is a 4 MB HiROM board: 64 banks of 64 KB, $400000 bytes in all. The CPU can see the same ROM bytes at several addresses:

CPU banks	What they show
$C0–$FF	The whole 64 KB of every ROM bank. These are the canonical addresses this wiki uses.
$40–$7D	The same banks again, minus the last two: $7E–$7F are work RAM instead.
$00–$3F	The upper half ($8000–$FFFF) of each bank; the lower half is RAM and hardware registers.
$80–$BF	A mirror of $00–$3F, used to select the faster ROM access speed.

So $C0:FF00 and $00:FF00 are the same byte, which is why the reset code, the internal header and the interrupt vectors at the top of bank $C0 are often written with bank $00. A file offset is (bank − $C0) × $10000 + address: $C1:0089 is at 0x010089 in the ROM file.

Only about 240 KB of the 4 MB is 65C816 code; the rest is graphics, music, maps and text, built from the original bytes, plus the SPC700 sound driver (7 KB, in $C7) and a compressed code module (26 KB, in $C3). The code size of each bank comes from the code survey: the matched code, the unmatched code a flow trace reaches from it and from the interrupt vectors, and an allowance for code reached only through indirect jumps; where the source covers the whole bank ($C0) it is the bytes of the routines that are code, not tables or fill.

Bank $C0: boot and core engine

The field engine, with the reset code, ROM header and interrupt vectors at the top of the bank. The whole bank is matched. In address order, the main groups:

• Game loop and location loading ($C0:0000–$C0:0B85): ReentryVectors, GameLoop, GameLoop_FrameBody, Field_EndOfFrame, LoadLocation and its steps, the field save and restore around bank-$C2 calls, and the field/battle hand-off ($C0:0283–$C0:0904).
• Scene changes and the field frame ($C0:0B86–$C0:2E66): Field_InitLoadState, Field_SceneChangeTick with the tile-animation handlers ModeE6_Handler … ModeFC_Handler and DefaultHandler, pause and menu input, the action button, the services ReentryVectors offers other banks, the fades, the message window step, the 16 window-effect hooks, the staff credits, the tile-animation list, the layer 2/3 drift steps, and ClearRAMDMA.
• Event script opcodes ($C0:2E67–$C0:56A5, $C0:5F6E–$C0:6D2E), the object scheduler and init ($C0:56A6–$C0:5D6D) and the opcode table Evt_OpcodeTable ($C0:5D6E).
• Graphics, palettes and slots ($C0:6D2F–$C0:7398): location graphics packs, VRAM and CGRAM uploads, and the tile-slot and palette-slot allocators.
• The map ($C0:7399–$C0:A80F): map set-up, layer redraws and edge builders, the edge uploads, Field_FrameUpdate and the D-pad, the leader's collision and tile effects, the layer scroll, and the party members' steps and animations ($C0:9E29–$C0:A33A).
• Objects and sprites ($C0:A810–$C0:EA62): object motion and view culling, the draw buckets, Oam_BuildShadow and the sprite placement routines, the animation tick and frame-build queue, the frame builders, Spr_LoadLargeObj and the tile buffer allocators.
• NMI ($C0:EA63–$C0:ECCB): NmiHandler, Field_WaitFrame, Credits_UploadLine and Oam_UploadShadow.
• IRQ ($C0:ECCC–$C0:F16F): IrqHandler, Irq_UploadTileAnim, and the message choice cursor it draws (Irq_DrawChoiceCursor and the row clears Irq_ChoiceCursorClearRow0–3).
• Leftovers ($C0:F170–$C0:F2FF): BankC0_OldBuildLeftovers, not code and, as far as found, never read: copies of the tails of the choice-cursor code just before it, "probably what earlier, longer assemblies of this part of the bank left behind", then $FF fill.
• Tables and the top of the bank: Rom_AngleTable ($C0:F300, the direction of a vector for run and rise 0–31, 256 steps per turn), Rom_DirToFacing ($C0:F700, the facing up, down, left or right for each direction), Rom_SineTable256 ($C0:F800, signed sine, 256 steps per turn) and Rom_SineTable ($C0:F900, |sin| for 1024 steps per turn), read by the field, battle and scene code; then BitReverseTable ($C0:FD00), RandomTable ($C0:FE00, probably the game's random bytes: a shuffle of 0–255), then Reset, the interrupt stubs, BitSet / BitClear, the wave tables, the cartridge header and the vectors ($C0:FF00 on).

See Engine core, Field event scripts, Frame cycle and NMI, Sprites & objects and Boot.

Bank $C1: battle engine

Nearly every byte of bank $C1 is code, and almost all of it is the battle. It opens with entry vectors and a same-bank service dispatcher ($C1:0000–$C1:0050, not matched yet). Also open are the behaviour-script handlers ($C1:8EAB–$C1:AC13) and the code after the long veneers ($C1:FDD3 on). Matched:

• $C1:007E–$C1:1F78: the frame wait, maths and shift helpers, number formatting, trig, the status bar, the battle menu with its tech and item lists and ready queue, and the battler frame decoder.
• $C1:1F79–$C1:4057: targeting, battler boxes and collision, the position queries, the PC and enemy animation ticks, status effects, poses and the enemy movers.
• $C1:4058–$C1:7FFF: service 4 and the action scripts (loaders, path search, threads, every opcode handler and their tables), then BankC1_OldBuildLeftovers ($C1:7C3D: not code, the cut-off remains of older assemblies of some of those tables, then $FF fill).
• $C1:8000 on: BattleSys_Main, the turn lists, the enemy behaviour script core and its tables, the battler checks, the turn helpers, the PC command runner, the target resolution, the tech menus and MP costs, the inventory and gold services, the effect types and their arithmetic (hit roll, damage, statuses, drain, steal), the 16-bit maths and random ranges, the hit records, the battle-end status clears, the hit modifiers ($C1:ED89–$C1:F204), the experience, levels and tech points ($C1:F205–$C1:FA60), Battle_SetupBattle and the long veneers for bank $FD.

See Battle engine and the battle pages it links to.

Bank $C2: scene mode, menu entry and text

GameLoop_Main jumps here for Loc_Id $01F0 and up. The scene half, $C2:0000–$C2:7FFF, is matched: the entry vectors, the scene mode's boot, NMI, VRAM queue, tasks, BG layer scrolls and redraws, sprite list, animation and scene scripts with all their ops, the mode handlers, scene loading, sound zones, the watchers and the party and object tasks, the direction helpers, the text decoder ($C2:57DF–$C2:6262), the map view and dial of modes 6 and 8, the screen effects and script routines with the extra-graphics loaders ($C2:754D–$C2:7DE3), and $FF fill up to $C2:8000. From the menu half: the entry vectors at $C2:8000, the menu's entry, thread scheduler, fades and VRAM queue ($C2:800E–$C2:840D), its NMI and IRQ handlers, the joypad reader and play-time clock ($C2:840E–$C2:85D5), the uploads, inventory, character and item helpers, cursors and list arrows ($C2:8663–$C2:8C35), and the PPU, RAM and new-game set-up ($C2:940D–$C2:960A). The menu's screens are not matched yet. See Scene engine, Menu and Text windows.

Bank $FD: main init and battle helpers

The reset code jumps here: MainInit at $FD:C000 sets up the CPU and the PPU, then jumps to GameLoop in bank $C0. Also matched: the battle helpers BattleFD_* ($FD:A982–$FD:B956) that bank $C1 calls with JSL, RandomTableFD ($FD:BA61, a copy of RandomTable), Ppu_SetBgLayout, the field HDMA set-up ($FD:C124–$FD:C2EA, $FD:D52D), and the location animation set-up with its vectors at $FD:FFF4–$FD:FFFC. The staff credits text at $FD:A000 is read by Field_ServiceUnk54.

Banks $CC, $CF and $FF: copies

So far only code that duplicates matched routines in other banks: a byte-identical copy of Battle_Mul8 in bank $CC (Battle_Mul8CC), bank $CF's own scaled sine (Battle_SinLookupCF) and four-digit number formatter (BattleMsg_FormatNumber4Digits), and a byte-identical copy of the wave tables in bank $FF (ScrollWaveFF_A/B). A JSR cannot leave its bank, so each bank that needs such a routine keeps its own copy.

Banks with no matched code yet

These banks have no slice map yet; each one gets its own as soon as a routine in it is matched.

No code at all, only data (graphics, music, maps, text): $C4, $C5, $C8, $C9, $CA, $CB, $D0, $D2, $D3, $D4, $D5, $D6, $D7, $D8, $D9, $DA, $DB, $DC, $DD, $DE, $DF, $E0, $E1, $E2, $E3, $E4, $E5, $E6, $E7, $E8, $E9, $EA, $EB, $EC, $ED, $EE, $EF, $F0, $F1, $F2, $F3, $F4, $F5, $F6, $F7, $F8, $F9, $FA, $FB, $FC, $FE.

Where the numbers come from

Every figure on this page is generated when the site is built, from docs/data/: progress.json and functions.csv, synced from the code repo by tools/sync_progress.py, and bank_survey.csv, the code and data size of each bank of the original ROM (from the code repo's symbols/code_survey.csv). Nothing here is typed by hand.