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Old 11-26-2010, 06:13 PM   #2
Senior Member
Join Date: Jul 2008
Posts: 278

Okay just updating this with some informational fixes.
Re-uploading the image won't really announce where I was wrong which is why I submit in the form of this post instead.

And I realize that probably no one cares about my thread , but if it suits moderator judgement do merge the posts.
Just taking notes for now.

"Conventions of MIPS32 Instructions"
When I wrote this image, I wasn't yet fully versed outside of simple historical modifications for each MIPS ISA. The bit-encoding conventions, however, apply to all MIPS instructions, for any ISA released under the MIPS architecture.
I was then falsely under the impression that MIPS64 meant support for 64-bit MIPS instructions. MIPS64, actually, means you can work with 64-bit numbers in registers or operate in 32-bit mode. I'm not sure offhand about PSX, but I know that N64 uses the MIPS64 architecture, through the VR4300 processor.

In the image I defined the opcode for register-encoded functions as 000000. This, indeed, is the only opcode defining the format as register-encoded, but I presumed at the time that there was no other way to create this kind of instruction. Coprocessor instructions, though, are sometimes R-type instructions under the instruction field classes defined by the COP[z] opcodes.

That's all for would-be modifications to the GIF I posted. Currently I'm writing an extended documentation covering all MIPS instructions using linear bitstring tables on the r4300i microprocessor and listings of the CPU registers, CP0 registers, and FPU registers. It's really cool, I think, and includes corrective (grammar and otherwise) naming of each instruction and field class name, information about class acronyms that is hard to extract from any official manual by MIPS. I think my work in progress is coming out as an agreeable source that is useful as a convenient reference for if you want to write basic N64 applications in machine code.
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