The procedure described in this section is formalized by the functions x87-binary-pre-comp and x87-sqrt-pre-comp.
In addition to those already noted, there are three differences between x87 and SSE pre-computation exceptions:
In the case of two NaN operands, the order of the operands is irrelevant. If the operands are distinct NaNs, then the one with the greater significand field is selected, but if the significand fields coincide, then the zero sign field is selected (x87-binary-pre-comp-val).
David Russinoff 2017-08-01