smsdat

Single-file HTML tool for SMS/GG homebrew development. Analyse ROM bank usage and diff RAM dumps, entirely in the browser — no server, no CDN, no tracking. Bilingual UI (FR/EN).

Two tabs

🗂️ Bank Analyzer

Reports the occupation of each 16 KiB ROM bank and the 8 KiB main RAM from a symbolic file — either WLA-DX .sym or SDCC .map. Format is auto-detected.

• Progress bar per bank (green < 60 %, orange < 85 %, red beyond)
• Sortable symbol table (address, name, area, size in decimal + hex)
• Per-symbol size bar overlaid on the row for a quick visual scan
• Treemap SVG built with a squarified layout (Bruls-Huijbregts-van-Wijk), hover tooltip showing address, size, % of bank, and area
• Global summary (banks used, ROM/RAM free, average occupation)
• CSV export

🔍 RAM Diff

Compares two SMS RAM binary dumps (8 KiB) and shows a hex grid of the differences.

• 16 × 512 hex grid with identical bytes greyed out and diffs highlighted (v1 red, v2 green)
• Filter to hide rows with no difference
• ASCII column on the right
• Context-aware tooltip when SDCC files are provided: load rom.map + _structures.h to see the struct name, field, type, and byte offset for the cell under the cursor

Usage

Open smsdat.html in a recent browser. Drag & drop the files or use the pickers. Everything runs locally.

Expected file formats

WLA-DX (Bank Analyzer)

The .sym file must be produced with:

wlalink -A -S linkfile out.sms

The -S flag is required — it writes the [definitions] section with the size of every symbol.

For accurate per-bank occupation, add a sentinel label _end_bank_N: (where N is the bank number, decimal or hex — your choice) right after the last data of each bank. Without it, WLA-DX inflates the _sizeof_ of the last label in each bank to reach the end of the 16 KiB slot, which makes banks look 100 % full even when they aren't.

.BANK 3 SLOT 2
.ORG $0000
    ...your data...
    pause_lut:
    .INCBIN "pause.bin"
_end_bank_3:   ; ← this label marks the true end of data

Banks with no _end_bank_N marker get an orange ⚠ badge, and a banner at the top of the results lists them.

SDCC (Bank Analyzer)

The .map file produced by sdld is used as-is. The devkitSMS convention is recognised (_BANK2 = 2 × 0x10000 + 0x4000, etc.). The tool:

• Merges area blocks re-emitted at every linker page break
• Keeps only symbols with a module (rom, banked_code_2, crt0) for display, and uses the linker-generated ones (_abs, s__CODE, …) purely as boundary markers for size computation
• Attributes to the last symbol of an ABS area the remainder of the area's declared size (necessary for SMS header areas, where the area's Addr field is nominal)

Known limitation: for __at() variables in RAM, the .map only contains addresses, not array sizes. The tool falls back to size = next_address − current_address, which can overestimate a variable's size when it is followed by a large unlabelled gap. Typical case: two __at(0xD100) uint8_t buf[256] with the next symbol at 0xD600 — the tool shows 1280 B instead of 256 B.

RAM Diff

• BIN: raw RAM binary dump (typically 8 192 B). Two files required.
• rom.map (optional): SDCC linker map, provides symbol names at each address.
• _structures.h (optional): C header with typedef struct and extern __at(0xADDR) type name; declarations. Used to resolve field names and types in the tooltip.

Code layout

• smsdat.html — single file, two independent IIFEs (BANK ANALYZER and RAM DIFF) sharing only LANG and an i18n callback list through the module scope. No ID or variable collisions.

License

GPL-3.0 license