Content cache

Master cache table

Symbol	RAM	Refs in arm9	Role
master cache table	`0x020AA740`	712	Indexed pointer-to-asset table; each slot identifies one loaded resource.
path string region	`0x020A1000..0x020A8000`	—	~28 KB of static path strings (131 unique paths). Each path is a NUL-terminated ASCII string like `"item/itemicon.ofs"`.
game state struct (pointer)	`0x021A55C0`	750	Pointer to runtime game state; most engine functions take this in R0.

Generic loader

All asset load requests funnel through the generic loader FUN_02009894:

FUN_02009894(
    void *table,        // r0 — usually 0x020AA740
    const char *path,   // r1 — pointer into 0x020A1000..0x020A8000
    u16 sub_index,      // r2 — TOC entry index inside the container
    u32 size,           // r3 — expected payload size (or 0 = use TOC length)
    u32 flag1,          // stack
    u32 type_code,      // stack — e.g. 0x7800 for item icons
    u32 flag2,          // stack
    u32 flag3           // stack
);

The loader reads the file at path from the NDS filesystem, decompresses it if LZS-wrapped, walks its RESO TOC to find sub_index, and writes a pointer/handle into the master cache table at the slot the caller has prepared.

Documented loader call sites

Caller	Path	Asset class
ov003	`2d/buyitem.lzs`	Shop chrome
ov003	`2d/itemorderwnd.lzs`	Shop order window
arm9 `0x02052D20`	`item/itemicon.ofs`	Item icon (per item-icon index)
arm9 `0x02052D20`	`global.lzs` entry 5	Item icon palette (256-color)
arm9 (boot)	`global.lzs` entry 0	Font (NFTR)
ov137	`2d/inputmagic/mgcall.ofs`	Magic glyph atlas
ov137	`2d/inputmagic/mgc80.ofs`	Magic glyph palette
various	`data/npc/NpcDataOfs.ofs`	NPC personality / portrait data
various	`data/item/itemname.ofs`	Item name strings
map overlays	`map/static.lzs`	3D map textures
map overlays	`map/weather/*.ofs`	Weather 3D models
title screen	`2d/mainmenu/title_pack.ofs`	Title-screen background variants (5 seasons)
title screen	`title/titledata.lzs`	Title splash sprites

Cache table entry layout (inferred)

Each slot in the master table is a struct accessed by:

struct CacheEntry {
    u32   flags;
    void *data_ptr;            // points into a heap-allocated decompressed RESO blob
    u32   size;
    u32   path_hash_or_id;
    ...
};

Exact layout has not been fully decoded; the loader and consumers agree on offsets via LDR/STR with specific [rN, #imm] offsets (e.g. [r5, #0x84] for the item-icon sub-index).

Generic asset loader at `0x02052D20`

Disassembly (THUMB, item-icon site):

02052D4C  LDR  R0, [PC, #0x30]      ; r0 = 0x020AA740   (master table)
02052D4E  LDR  R1, [PC, #0x34]      ; r1 = 0x020A55D8   ("item/itemicon.ofs")
02052D50  LSLS R3, R3, #0xA          ; r3 = 0x7800       (flags / type_code)
02052D52  BLX  0x02009894            ; call generic file-loader
                                     ; r2 = u16 sub-index from caller's [r5+0x84]

Source

notes/phaseA_ghidra/DISCOVERIES.md — cache + loader analysis
arm9_full_plaintext.bin @ 0x02009894 — generic loader
arm9_full_plaintext.bin @ 0x02052D20 — item-icon loader thunk