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 21 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 + 21 * 0x20, allocates the destination
RAM region at 0x02155a00, decompresses
the body in-place (if compressed), and resolves any external
relocations.
To inspect this overlay outside the running game, decompress
overlay/overlay_021.bin with
ndspy.codeCompression.decompress() (Python ndspy library)
and load the resulting plaintext into Ghidra or
IDA at base address 0x02155a00. The
raw Ghidra auto-analysis dump used to populate this page lives at
notes/overlay_knowledgebase/raw/ov021.json;
the per-overlay descriptive markdown is at
notes/overlay_knowledgebase/ov021.md.
Embedded strings
1 UTF-16 LE string 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.
-
inputmailβdata/inputmail.lzs
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 15 functions
| # | Address | Size | Calls | Strings | Role hint |
|---|---|---|---|---|---|
| 1 | 0x02155a74 | 32 | 3 | 0 | trampoline / small helper |
| 2 | 0x02155f2c | 6 | 0 | 0 | trampoline / small helper |
| 3 | 0x02155f34 | 30 | 3 | 0 | trampoline / small helper |
| 4 | 0x02155f54 | 24 | 1 | 0 | trampoline / small helper |
| 5 | 0x02155f6c | 176 | 7 | 0 | code |
| 6 | 0x02156028 | 64 | 4 | 0 | code |
| 7 | 0x02156070 | 18 | 2 | 0 | trampoline / small helper |
| 8 | 0x02156088 | 10 | 0 | 0 | trampoline / small helper |
| 9 | 0x0215609c | 10 | 0 | 0 | trampoline / small helper |
| 10 | 0x021560b0 | 216 | 10 | 1 | refs: FROM |
| 11 | 0x02156198 | 68 | 4 | 1 | refs: inputmail |
| 12 | 0x021561e0 | 32 | 3 | 0 | trampoline / small helper |
| 13 | 0x02156200 | 10 | 0 | 0 | trampoline / small helper |
| 14 | 0x0215620c | 260 | 9 | 0 | code |
| 15 | 0x02156338 | 12 | 1 | 0 | trampoline / small helper |
Open questions & conflicts
Open questions / unknowns
- Auto-analysis identified 15 functions covering 968 of 2528 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 0 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/ov021.md - Raw Ghidra dump:
notes/overlay_knowledgebase/raw/ov021.json - Overlay-system explainer: overlays system
- Plain-English overlay primer: overlay knowledgebase