(09-17-2012, 10:30 AM)Amak Wrote: I believe the PS2 had an actual PS1 console in it.
Almost, though there are differencies too.
The main CPU of the PS2 is a MIPS processor called EE (Emotion Engine !!!), and this CPU 'lives' in an address space containing 32 MB RAM, the PS2 BIOS ROM, and some other stuff.
Most I/O processing is handled by a slave processor, which is also a MIPS type and aptly named IOP (I/O Processor), and this CPU 'lives' in an address space containing 2 MB RAM and some other stuff. (The 'other stuff' naturally includes a means for these CPUs to interact with each other too.)
The IOP is nearly identical to the CPU of a PS1 console, and it has direct access to most I/O devices in its address space (like a PS1 CPU does), so that is what a PS2 uses for running PS1 games.
But when running games in PS1 mode, the PS2 system is somewhat 'remapped', and its components interact with each other differently than they normally do. (Most significantly, the IOP is no longer a slave...)
PCSX2 development has been focused on emulating only the normal PS2 mode of the console, so PCSX2 is not capable of emulating the remapped PS1 mode as well. That would require major changes, which in turn would demand long and intense development work.
So the question is if we would rather see such work invested in adding a PS1 mode, or if we would instead prefer it being invested in further improvements of the PS2 mode, raising game compatibility and improving the PS2 graphics hardware emulation...?
Personally I prefer keeping future work focused on the PS2 mode, since there are satisfactory PS1 emulators already, while the PS2 mode of PCSX2 still is a work in progress. If/when that is ever perfected, it may be time to look at the possibility of also emulating the PS1 mode, but not at present.
Best regards: dlanor