A sum of two products
Two products added together — you see this shape everywhere: a 2D dot product, a determinant, a complex multiply. On the face of it that's two multiplies and an add, but only one fmuls shows up, because the second product gets folded into the add by fmadds.
Take cross(p, q, r, s), which computes p*r + q*s:
fmuls f0, f2, f4 # f0 = q * s (one product, standalone)
fmadds f1, f1, f3, f0 # f1 = p*r + f0 = p*r + q*s
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The compiler did q*s first as the standalone fmuls, then swept p*r and the running sum into a single fmadds. (fmadds fD, fA, fC, fB = fA*fC + fB.) Which product lands in the lone fmuls and which rides in the fmadds is up to the compiler. What you care about is the operand registers, since they tell you which two arguments multiply together. The four floats come in across f1–f4.
Your target has the same fmuls → fmadds skeleton. Read the operand registers, pull out the two products, and check that they are added.
Your task
Write func_80265844 to reproduce the assembly above.