Taken from byuu's homepage on 06/08/2011
Cx4 PageCx4 LLE2011-06-08
Thanks to the efforts of Jonas Quinn for discovering that the Cx4 program ROM is actually embedded inside the Mega Man X2/X3 mask ROMs themselves, Segher for reverse engineering a high level understanding of the instruction set, and Overload for exploiting these to dump the data ROM, we now have sufficient information to start on low-level emulation of the Cx4. Which means it's my turn.
I'd also like to thank Dr. Decapitator for the high-res scans of the Cx4, which allowed us to identify much information about the chip that will be invaluable in emulating it; and Lukasz for the donation that made this possible.
While we currently have high-level emulation (HLE) support for the Cx4, LLE will bring improved accuracy with actual timing support and bit-perfect math calculations. That is, assuming we are successful.
I am able to host the cx4.bin file this time, as the program ROM is separate and part of the MMX2/3 mask ROMs. The data ROM is nothing more than five math tables (inverse, square root, sin, cos, tan) which are not copyrightable. I do not plan on embedding it into bsnes, as I would like to allow for the possibility of using a custom data ROM ala the uPD7725/96050 emulation.