|Category||Compression / Decompression|
|Release Date||11 February 2020|
|Last Modified||12 February 2020|
Simple Tools is a set of two simple utilities (a packer and an unpacker) for graphics. The compression algorithm is very simple and effective in the case when the image contains many repeating bytes in a row (pictures with monochrome backgrounds, for example). Compression is only repeated bytes in a row, while the rest of the data is not compressed (RLE). Images of formats (1 - 15) bits per pixel can be compressed quite well (4-7 times). Included with the utility is a description of the compression algorithm and ready-made solutions (code for unpacking) for the MIPS-R3000A CPU (used in Sony Playstation) and Super Hitachi 2 (installed in Sega Saturn). The code of the unpacker takes less than 20 instructions and in the case of the SH-2 CPU, for example, it will take no more than 40 bytes.
Summing up, if you are faced with packed data and you really don’t feel like messing with the original packing / unpacking algorithm (or annoy someone with this matter) and there is some free space in the game’s resources, you can use the Simple Tools.
PS: Even if the console uses a different CPU than the ones described above, knowing the compression algorithm and assembler of the current CPU, you can write your own code and optionally add it to existing ones. It is enough to create a text file with a description and put it in the root folder of the utility, thereby contributing to the Simple Tools project.