AW: [RFC] Adding division/modulo on arbitrary precision integers to libgcc

[Matthias Gehre <matthias.gehre@amd.com>]

> Note that each architecture also needs to specify its _BitInt ABI
> (including such things as whether the values of padding bits inside the
> size of the _BitInt type, or outside that size but within a register used
> for argument passing or return, have specified values or are arbitrary).
> HJ has a proposal for x86_64 on a branch of the ABI, but it hasn't been
> merged to master yet.
Thanks, I didn't know that this is currently in progress.
This is still slightly different, because the ABI can choose to make different
choices for _BitInt(N) depending on N, but here we need to specify an interface
that works independent of N.

> This proposed interface doesn't say anything about what aliasing is or
> isn't permitted among the four arrays pointed to.
Good catch. I would lean into saying that none of the four arrays must alias
because allowing them to alias would require most implementations to allocate
extra scratch space.
What do you think?

--
Joseph S. Myers
joseph@codesourcery.com