A.5.319 UCOMISS: Unordered Scalar Single-Precision FP compare and set EFLAGS
UCOMISS xmm1,xmm2/m128 ; 0F 2E /r [KATMAI,SSE]
UCOMISS compares the low-order single-precision FP numbers in the two
operands, and sets the ZF, PF and CF bits in the EFLAGS register. In
addition, the OF, SF and AF bits in the EFLAGS register are zeroed out.
The unordered predicate (ZF, PF and CF all set) is returned if either
source operand is a "NaN" ("qNaN" or "sNaN").