RISC

/prog/, I'm working on a RISC instruction set that is more RISC than any RISC out there. I've devised an instruction format, plus fifteen core instructions that should suffice for any programming out there. The instruction format, instruction forms, and instructions can be found here:

http://jsbin.com/ekuwap

Any comments or suggestions?

>>3
I'm pretty sure that I'll be missing some important instructions, so a few more bits of opcode headroom is a good idea. This is my first venture into instruction set design, after briefly studying the x86 and PowerPC instruction sets. Do you know of any 'holes' in my instruction set? For example, I saw a 'system call' instruction, mnemonic sc, in PowerPC. I don't understand how that works at all, but I can gather that it's fairly important.