COMMONSP.IMG — Common Sprite Bank

Compact startup graphics bank loaded during the VGA bootstrap phase. Contains common UI sprites and shape records used across multiple game screens. Loaded by DARKLAND.EXE startup helper 1699:179A0 after mgraphic.exe is installed.

Extension

COMMONSP.IMG

Location

DARKLAND\

Byte order

Little-endian (16-bit)

Size

4,078 B fixed (0x0FEE) — length word + 14-entry offset table + 4,048-byte payload

Compression

None

Magic

None — payload_length word (0x0FD0) at 0x00

Status

Partial

Source

RE — direct file inspection + DARKLAND.EXE startup analysis (2026-04-16)

Reverse-engineered from direct file inspection and DARKLAND.EXE startup analysis (2026-04-16).

File Layout

Offset 0x0000:  word       payload_length = 0x0FD0
Offset 0x0002:  word[13]   payload_offsets — 13 non-zero offsets into payload
Offset 0x001E:  byte[0x0FD0] payload

The leading word is the payload length (0x0FD0 = 4048). The header is 0x001E bytes: 0x001E + 0x0FD0 = 0x0FEE exactly matches the file size.

The offset table begins at word 1 and contains 14 entries (including a zero-valued first entry). Only the 13 non-zero entries are meaningful offsets into the payload. This count is an exact match for the 13 startup globals seeded from this file: A3D6, A3E5, A2E9, A33B, A33E, A392, A660, A662, A664, A666, A626, A628, A2E5.

Offset Table

Slices 0–10 are tiny entries; slices 11 and 12 are short structured blocks; slice 13 is the dominant image/resource body.

Payload Contents

Small slices (0–10)

Dominated by low byte values such as 0x05, 0x07, 0x08, 0x0F, and small counter-like bytes (0x17). Best current reading: dimension tables, hotspot entries, or group descriptor records.

Large body (slice 13)

The 3807-byte body contains compact indexed art records with short embedded ASCII labels. Dominant byte values are in the range 0x96..0x9F — consistent with palette-indexed sprite data.

Each named subrecord follows a common pattern: a label string, then a width byte, then a height byte, then the pixel data (possibly with per-row length encoding).

Selected subrecords identified by label:

Note: Some label bytes are immediately followed by the width byte which happens to fall in the printable ASCII range (0x36 = '6'). Strings such as HALLEN6 are correctly read as HALLEN + width 0x36, not as a 7-character label.

How the Engine Uses This File

The startup helper 1699:179A0:

1. Loads COMMONSP.IMG into the staging buffer set up at C103:C105.
2. Calls 0DDD:0004 (a shared object-allocation service) with the first payload word and tag string CnnmSp; stores the returned handle in 9C42.
3. Calls 0EC4:2EB4 (a far memory-copy helper) with the payload body and the returned base.
4. Walks the 14-entry offset table and seeds 13 startup globals in regions A2xx, A3xx, A6xx by rebasing file-relative offsets against the installed base.

Later presentation logic compares [9C42] against runtime-selected resource handles, confirming that COMMONSP.IMG is installed as a durable common-asset bank rather than a one-shot load buffer.

Relationship to BATTLEGR.IMG

COMMONSP.IMG belongs to the same named image-bank family as BATTLEGR.IMG. Both files begin with a payload-length word, carry a multi-entry offset table, and embed compact named subrecords. BATTLEGR.IMG uses a 0x194-byte header and labels like $VILLA0, $MINET3, $CITYW0.

Confidence

High for the file layout and offset table.

Medium for the exact per-record row encoding and the semantics of each small slice. The label/dimension pattern is well-supported but the exact pixel-row encoding is not yet fully solved.