On Mon, 14 Jan 2019 at 22:48, Alex Bennée <alex.ben...@linaro.org> wrote: > > > Richard Henderson <r...@twiddle.net> writes: > > But perhaps > > > > unsigned __int128 n = (unsigned __int128)n1 << 64 | n0; > > *r = n % d; > > return n / d; > > > > will allow the compiler to do what the assembly does for some 64-bit > > hosts. > > I wonder how much cost is incurred by the jumping to the (libgcc?) div > helper? Anyone got an s390x about so we can benchmark the two > approaches?
The project has an s390x system available; however it's usually running merge build tests so not so useful for benchmarking. (I can set up accounts on it but that requires me to faff about figuring out how to create new accounts :-)) thanks -- PMM
