Although anyone is free to take on the idea if they have enough experience and are willing to do it without too much pressure. But seeing as nobody has started doing it yet despite being a great idea, I assume everyone is already too busy with their projects or there's just not enough discoveries about the PRIZM yet, or people are not yet experienced enough in PRIZM development to achieve something like an emulator.

Also another worry I got is about grayscale: The PRIZM screen only allows a maximum of 21 frames per second (22 on some calcs IIRC). A 83+ emulator would absolutely need stuff like Wabbitemu LCD settings so the user can alter how the screen gets refreshed, in order to accomodate grayscale games that flickers a bit more than others (such as Axe and TI-BASIC games). At 21 FPS maximum this might cause a few problems getting perfect-looking grayscale, right?

If somebody links me to some assembly info for the Prizm, I would not mind attempting to write an emulator. I wrote an emulator for a made up system on my TI-84+ a while back, and in assembly, the only difficult things would be hardware emulation, including the keymap, LCD, timers, and linkport. I do have enough knowledge of the z80, I believe, to write an emulator.

If somebody links me to some assembly info for the Prizm, I would not mind attempting to write an emulator. I wrote an emulator for a made up system on my TI-84+ a while back, and in assembly, the only difficult things would be hardware emulation, including the keymap, LCD, timers, and linkport. I do have enough knowledge of the z80, I believe, to write an emulator.

Here's the SH3 instruction set:
http://documentation.renesas.com/doc/products/mpumcu/rej09b0317_sh_3sm.pdf

You could try porting the Wabbitemu core, but you'd probably get 1 fps from it since it's very unoptimized. A full SH3 ASM port is probably necessary...

Well, with CPU emulators it's best to write one specifically for the CPU you're using, in Asm. That way, commands can be directly linked, like how AND functions virtually identically across instruction sets. In C, doing an AND command is much more than the single operation.

Yes, exactly. Emulating a CPU in assembly is a cakewalk because of that. The z80 is a very simple cpu that has structures that exist on almost all other newer CPUs. For example, loads, bit operations, and addition/subtraction are available on almost all CPUs and that is the brunt of the operations available on a z80. Emulating the hardware is the tough part, especially the link port (which is a little different on the Prizm, but this may be possible), the LCD, timers, and USB (which I probably won't even attempt). I hope to have enough time for this in the summer (but then again, I hope to be doing GSoC which will eat up a lot of my time).

The hard part about emulating other CPUs on the SuperH is that there is only one flag that can be affected by various operations. For addition/subtraction, that means you'll have to detect carry, overflow, sign, zero flags separately, plus the odd half-carry flag that's already a pain to emulate on most architectures.

It would probably be faster to only calculate the half-carry, 3FLAG, and 5FLAG if the emulator hits a PUSH or DAA.  All you have to do is save the operands and flags for one flag-affecting calculation back.

When the emulator hits a PUSH or DAA instruction, the emulator can calculate the flags using the saved operands.

Good point >.> The half carry will be fun to work through

As a quote from the link JosJuice provided:

• Sixteen 32-bit general registers (eight banked registers)
• Five 32-bit control registers
• Four 32-bit system registers (SH-3)
• Six 32-bit system registers (SH-3E)

There are a few I am not sure what permissions are like on certain registers, though :? (I probably have easy access to the sixteen and the others might be more difficult). Also, I really like this instruction set o.o