The other finisher
Equality's twin. != starts from the same difference-detector — XOR — but needs the opposite finisher: not "is the difference zero?" but "is it nonzero?". You've already met that move, back when you tested a bit:
sltu v0, zero, a0 # 0 < x (unsigned)? — 1 for any nonzero x
jr ra
nop
That's the whole of return x != 0; — "zero is unsigned-less-than x" is true for every value except zero itself. Bolt the XOR on the front and you get != for two values: difference first, nonzero-test second. The pair of finishers side by side:
sltiu d, s, 1 — "s == 0" — closes an equality.sltu d, zero, s — "s != 0" — closes an inequality.
Both lean on unsigned comparison against the edge of the number line, and they're easy to tell apart at a glance: == puts the 1 in the immediate, != puts zero in the middle operand. Neither line makes sense alone — when you spot either one, look up a line for the xor/xori (or other value) feeding it, and read the two lines as a single C comparison.
The target materializes != between its two arguments. You know both halves; write the one-line C that summons them.
Your task
Write func_80023ab0 to reproduce the target assembly.