DS game only 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 123 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 + 123 * 0x20, allocates the destination
RAM region at 0x021601c0, decompresses
the body in-place (if compressed), and resolves any external
relocations.
To inspect this overlay outside the running game, decompress
overlay/overlay_123.bin with
ndspy.codeCompression.decompress() (Python ndspy library)
and load the resulting plaintext into Ghidra or
IDA at base address 0x021601c0. The
raw Ghidra auto-analysis dump used to populate this page lives at
notes/overlay_knowledgebase/raw/ov123.json;
the per-overlay descriptive markdown is at
notes/overlay_knowledgebase/ov123.md.
Embedded strings
No UTF-16 LE strings are embedded directly in this overlay's binary. Any text it displays at runtime comes from a container file loaded via the content cache.
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.
-
mapnameβdata/2d/mapname.lzs
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.
-
2d/mapname.lzsβ 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.
Show all 8 functions
| # | Address | Size | Calls | Strings | Role hint |
|---|---|---|---|---|---|
| 1 | 0x02160254 | 100 | 7 | 0 | code |
| 2 | 0x021602c4 | 412 | 22 | 1 | refs: 2d/mapname.lzs |
| 3 | 0x02160480 | 8 | 0 | 0 | trampoline / small helper |
| 4 | 0x02160488 | 120 | 9 | 0 | code |
| 5 | 0x02160504 | 74 | 4 | 1 | refs: mapname.lzs |
| 6 | 0x02160558 | 6 | 0 | 0 | trampoline / small helper |
| 7 | 0x02160564 | 412 | 25 | 0 | high-fan-out (likely dispatcher / setup) |
| 8 | 0x02160714 | 12 | 1 | 0 | trampoline / small helper |
Open questions & conflicts
Open questions / unknowns
- Auto-analysis identified 8 functions covering 1144 of 1472 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
- Partial overlap: prior-pass had `['mapname']`; Ghidra adds `['2d/mapname.lzs']`.
Source
- Per-overlay markdown:
notes/overlay_knowledgebase/ov123.md - Raw Ghidra dump:
notes/overlay_knowledgebase/raw/ov123.json - Overlay-system explainer: overlays system
- Plain-English overlay primer: overlay knowledgebase