Editing Wikifang:Telefang 2 Translation Patch/NatsumeGBA compression
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"Malias2" compression is the compression system used in Telefang 2. Like its namesake [[Wikifang:Telefang_1_Translation_Patch/Malias_compression|Malias compression]], it is a predictable variation upon LZ77. Why they didn't just use the GBA BIOS LZ77 compression functions is beyond me. (Seriously, why? Unless Nintendo doesn't document their own BIOS functions...) | |||
== | == Malias2 format == | ||
(All reads are little-endian, the default endianness of ARM, unless otherwise specified) | (All reads are little-endian, the default endianness of ARM, unless otherwise specified) | ||
Like | Like Malias, it has a header and bundles. The header is different - instead of a single "is compressed" byte, there is instead a 16-bit magic value 0x4C 0x65 ("Le") followed by a 32-bit size value. Only the lower 24 bits of this value are actually used. If the magic is invalid, something else happens (I'm not sure yet). The size value is how many bytes of uncompressed data should be written. | ||
Malias2 commands are encoded as bundles of four commands. There are four types of commands. Thus, each bundle's command list fits snugly within a single byte. Command lists are read from the lower bits upwards, two bits at a time. | |||
During this discourse we will talk about a "write head". This is the location of the next byte to write to in memory. | During this discourse we will talk about a "write head". This is the location of the next byte to write to in memory. | ||
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== See Also == | == See Also == | ||
* [[User:Kmeisthax/Findings/2012/2/4/Malias2_Listing |A disassembly of the Telefang 2 decompression routine]] | * [[User:Kmeisthax/Findings/2012/2/4/Malias2_Listing |A disassembly of the Telefang 2 decompression routine]] | ||
* Coming Soon - Codemodule support for | * Coming Soon - Codemodule support for Malias and Malias2 | ||
* [https://github.com/Sanky/romhacking/blob/master/telefang/puneedle.py puneedle.py] is a Python | * [https://github.com/Sanky/romhacking/blob/master/telefang/puneedle.py puneedle.py] is a Python Malias2 decompressor implementation. |