Currently, unordered floating point comparisons ("ucomiss", "ucomisd") require special handling when one of the inputs (src1, src2) is NaN. This is because the unordered condition (ZF=1, PF=1, CF=1) overlaps with the less than (CF=1) and equal (ZF=1) conditions.

AVX10.2 adds new comparison instructions ("ucomxss", "ucomxsd") that remove this limitation by setting the EFLAGS register differently to allow these relationships to be tested independently. Essentially, unsigned tests are used for greater than conditions and signed tests are used for less than conditions.