A second register file
Floating-point math doesn't happen in v0 and a0. The console carries a floating-point unit — coprocessor 1 — with its own bank of 32 registers, and float values live their whole lives over there. Like the integer side, the registers go by job names:
fa0, fa1 — the first two f32 arguments.fv0 — the float return value.ft0, ft1, … — float temporaries, burned freely.
(In hardware terms those are $f12, $f14, $f0, $f4… — you'll meet the raw numbers in other people's notes, but the diff always shows the friendly names.)
Here's dampF(a, b), which returns a - b:
sub.s fv0, fa0, fa1 # fv0 = a - b
jr ra
nop
Read it exactly like integer code with two substitutions. The .s suffix means single precision — an f32 operation (.d, for f64, arrives later in the chapter). And the operands are FPU registers — but the grammar is identical: destination first, then the inputs, in source order. sub.s fv0, fa0, fa1 is fa0 - fa1, order mattering just as much as integer subu.
One thing you won't see: any a0 or v0. A function whose inputs and output are all floats never touches the integer bank at all — argument passing, math, and return all stay on the FPU side. When the two worlds do need to talk, there's a border crossing with its own toll; a few lessons from now.
The target is a single .s operation on the two arguments. Its mnemonic is the function.
Your task
Write func_803b6580 to reproduce the target assembly.