- Exomizer, now at versione 3.02, is the most efficient in terms of compression, although its decompression speed is also the slowest, and the decompressors need an extra 256 byte further space for calculations;
- ZX7 is the least efficient for large files, but used in conjunction with RCS is the most efficient solution for packing screen files;
- Aplib seems to stay in the middle - not as efficient as Exomizer, but more than ZX7, and can count on faster Z80 decompressor codes.
I downloaded the compressor executable and made a quick test with my typical scenario of use: squeezing AGD-authored levels, and their additional code, of large games into the 16384 bytes of the 128K models' ROM banks. I employed the three levels of Sophia II for the test and compared the results with ZX7 and Exomizer 3.02:
Code: Select all
Lev. Unc. ZX7 APC Exo ----------------------------------- 1 26758 15574 14875 14978 2 27051 16291 15604 15647 3 27488 15844 15245 15306
The post's author included two Z80 decompressors written by Dan Weiss (Dwedit), utopian and Jaime Tejedor Gomez (Metalbrain). He optimized one of them for size and the other for speed. The former in particular is 140 bytes long, and with a slight modification at the cost of 4 bytes more, can be made 20% faster. I tried it and it is noticeably faster than the F0 Exomizer 3 Z80 decompression routine (also by Metalbrain and optimized by Antonio Villena and Urusergi), which is also longer at 163 bytes.
These two decompressors were written for the SjASM plus cross-assembler, which uses non-standard formats for labels and other elements (ADD A instead of ADD A,A etc.). I modified them to comply as much as possible with the standard Z80 format and with the Pasmo 0.5.4 beta 2 cross-assembler in particular. I included all of the decompressors in a ZIP file, together with the executable, a .BAT file for easier use and a small text note. You can download it from here.