ov127 — overlay detail

Header

Numeric metadata for this overlay as read from the overlay table at ROM offset 0x8DE00 (per-entry stride 32 bytes). Function counts, data-item counts, and the call-graph fan-out are from a Ghidra 11.3.1 headless auto-analysis pass.

Reading the binary

The overlay ships on the cart at file ID 127 under the BLZ code-LZ compression wrapper (the same backward-LZ scheme Nintendo uses for executable ARM9 code). At load time the engine reads the overlay table entry at ROM offset 0x8DE00 + 127 * 0x20, allocates the destination RAM region at 0x02161680, decompresses the body in-place (if compressed), and resolves any external relocations.

To inspect this overlay outside the running game, decompress overlay/overlay_127.bin with ndspy.codeCompression.decompress() (Python ndspy library) and load the resulting plaintext into Ghidra or IDA at base address 0x02161680. The raw Ghidra auto-analysis dump used to populate this page lives at notes/overlay_knowledgebase/raw/ov127.json; the per-overlay descriptive markdown is at notes/overlay_knowledgebase/ov127.md.

Embedded strings

8 UTF-16 LE strings live inside this overlay's compiled binary. These addresses are absolute (inside the overlay's RAM image after load). The text is stored as little-endian UTF-16 code units, NUL-terminated.

Container references

Distinct container basenames referenced by this overlay. Each is loaded via the content cache by passing the basename string to a lookup that resolves it to a file ID in the ROM's FAT. The path column shows the file's location in the clean extract, where resolved.

• NpcRoom → data/npc/NpcRoom.ofs
• plane → data/model/map/plane/model/plane.ofs
• room → data/model/item/room.ofs
• shop → data/model/item/shop.ofs

Unresolved

These container basenames appeared in the overlay's string table but no file of that name was found in the clean extract. Most are false-positive ASCII matches (function names, register maps, fragments of other strings); a few may be containers that the overlay names but never actually opens. Listed for completeness.

• /map/plane/plight.ofs — no matching container found in clean extract
• Fas00_board00 — no matching container found in clean extract
• display — no matching container found in clean extract
• map/attribute/attrplane.ofs — no matching container found in clean extract
• map/fish/fishdata.ofs — no matching container found in clean extract
• map/insect/insdata.ofs — no matching container found in clean extract
• model/item/tv_tex.ofs — no matching container found in clean extract
• model/map/fish/Tfm_item.ofs — no matching container found in clean extract
• model/map/fish/fm_item.ofs — no matching container found in clean extract
• model/map/plane/model/plane.ofs — no matching container found in clean extract
• model/map/plane/tex/leaf_tex.ofs — no matching container found in clean extract
• model/map/plane/tex/tex%d/Tplane.ofs — no matching container found in clean extract
• model/meffect/meffect.ofs — no matching container found in clean extract
• model/meffect/mefftex.ofs — no matching container found in clean extract
• model/shop/model/sell_seat.ofs — no matching container found in clean extract
• model/shop/tex/Tsell_seat.ofs — no matching container found in clean extract
• npc/NpcRoom.ofs — no matching container found in clean extract
• pc_shop/selling/saleinfos.lzs — no matching container found in clean extract
• sh_leaf00 — no matching container found in clean extract
• sh_leaf00_0 — no matching container found in clean extract

Function list

Functions Ghidra auto-identified inside this overlay's RAM range. Names prefixed FUN_ are auto-generated from the function's entry address; size is in bytes; the "calls" column counts both intra-overlay branches and external ARM9 call targets. The "strings" column counts how many UTF-16 LE strings each function references.

Open questions & conflicts

Open questions / unknowns

• Auto-analysis identified 164 functions covering 23286 of 46336 overlay bytes.
• Function names are auto-generated `FUN_<addr>`. Manual renaming based on call-graph + string-ref analysis is a follow-up.
• BSS size is 32 bytes; Ghidra-imported overlay does not include BSS so any references into the BSS range appear as unresolved.

Conflicts with the prior shallow pass

• No major conflicts detected with prior-pass `overlay_role_final.json` record.

Source

• Per-overlay markdown: notes/overlay_knowledgebase/ov127.md
• Raw Ghidra dump: notes/overlay_knowledgebase/raw/ov127.json
• Overlay-system explainer: overlays system
• Plain-English overlay primer: overlay knowledgebase