On Wed, Jul 8, 2020 at 9:07 AM Richard Henderson <richard.hender...@linaro.org> wrote: > > On 7/6/20 4:47 PM, Max Filippov wrote: > > pickNaNMulAdd logic on Xtensa is the same as pickNaN when applied to > > the expression (a * b) + c. So with two pickNaN variants there must be > > two pickNaNMulAdd variants. > > "Is the same as"? > > I question the non-use of the infzero parameter. > > When infzero, (a * b) = (Inf * 0), which will produce a default QNaN. Your > sentence above would suggest that pickNaN is applied twice, so that if > use_first_nan, the default nan is chosen above any nan within c.
Apparently the description it's wrong: only NaNs in arguments are considered, default NaN produced as a result of (a * b) is never chosen when c is NaN. > In addition, is the invalid flag raised for (Inf * 0) + NaN? Does that happen > regardless of the use_first_nan setting, or does the whole operation > short-circuit? Flag setting happens regardless of which NaN is chosen. I'll post v3 with a fix for this and additional tests. -- Thanks. -- Max
