Hammer (compression)

File Format
Name	Hammer (compression)
Ontology	Electronic File Formats Compression Hammer (compression)
Released	~1994

Hammer (sometimes abbreviated HMR) is a compressed file format used by the RISC OS games Asylum and Oddball. The format and the games were developed by Andy Southgate.

Identification

Files begin with ASCII "Hmr", followed by a byte with value 0x00 or 0x01.

Files with 0x01 at offset 3 use a slightly different compression scheme, and are apparently expected to decompress to a FastSpr sprite file.

Specifications

• Gamesuite Documentation → Hammer file format

Software

• nobrainer (Includes RISC OS binary, and portable source code.)
• Hammer Decompressor

Sample files

• dexvert samples — archive/hammer
• Asylum → asy202.zip → ... (e.g. AsyNu/!Asylum/!Id/{Brain,FSPAliens})

Links

• asylum.acornarcade.com