ummm LOL
Where do we get these people? All emus are reverse engineered, at the start. Ultra64 was as was psemu-pro (predecessor to expse). Docs will not cover all aspects of the hardware's variances, both across different released versions (say PSX 1997 and PSX 1999 - different CDroms and different rom BIOS) and in different situations. Rememeber that game devs sometimes exploits limitations or bugs in the hardware to achieve some of what they want.
The REAL reason why PSX emulation isn't still perfect has to do with its annoying and difficult to emulate amorphous memory access system. The PSX was nothing like current PC's of the day in terms of archictecture. Therefore the coders had to deal with technology that just was not standard outside of the PSX.
The N64 on the other hand was built with some WELL KNOWN parts, not the least of was its SGI rendering engine. You'll notice that since DX9 cards have been proliferating a couple of new plugins have arrived for PJ64 etc. Why? Well the N64 used a technology that was a predecessor to what's known as PS or Pixel Shaders. Direct64 implements use of the Shaders on your DX9 card to emulate the N64 (so far underemulated) Frame Buffer effects and mulitexturing shaders. You can see the IMMEDIATE difference in a game like Banjo Kazooie. Everything just looks more cartoony and the characters are shaded a whole lot nicer.
Yes I realise this went off topic but I did cover two emulators in order to illustrate my answer.
Hope the mods don't mind
Cheers,
mezkal
Cheers,
Mezkal
