GuestLog in

spAsm is what you would have used years ago for writing MIPS R3000 code, both for hacking and programming homebrew software.

Why did I say "would have"? Because at the moment there's much better we could use for the PlayStation and it's called "armips". spAsm was never intended for injecting new code into a game, even though it has an option to output pure binaries that could be inserted later with an external program. Yes, you're gonna need an extra inserter for each section of code using a different .org location. That's really annoying if you have many new code sections and several asm files to compile and inject every time. Also, this program tends to do weird stuff on newer Operating Systems, like refusing to boot entirely.

So my personal advice is to abandon spAsm and switch to armips in order to make your life easier when you're about to hack PlayStation, DS and GBA titles (and soon more MIPS-based machines). Your mental sanity is gonna appreciate a lot.