Hi Matthew, Just wanted to add a couple of MIPS-specific things on top of what Joseph said:
Matthew Fortune <matthew.fort...@imgtec.com> writes: > The MSA patch as submitted is another variation of O32 ABI which could > be described as O32+FP64+MSA(+nan2008) and would be link incompatible > with both O32 and O32+FP64(+/-nan2008). The same of course applies to > N32/N64 being link incompatible with N32/N64+FP64. This may make it > difficult to have a small part of an application optimised with MSA but > the rest of the code ignorant of MSA, in your experience do you think > that will be an issue? FWIW, n32/n64 is always fp64 -- we don't support an fp32 version. And as you imply, o32+fp64 is already an established ABI so I think we have to support the current form alongside any new one. I agree with Joseph that it'd be better to realign the stack dynamically instead. This is what x86 does, so it's well tested within gcc. Also, I think there was a possibility of adding a 256-bit form of MSA in future, is that right? So if we added extra static alignments, would we need a separate ABI for 256-bit MSA too? > We (MIPS) have several discussions ongoing regarding ABIs on a variety > of mailing lists so I'm trying to collect as much input as possible to > inform future plans. > > One part of the patch that I don't believe you commented on is the > change of stack alignment for both existing O32+FP64 and new > O32+FP64+MSA. Did this seem OK? No, sorry, not sure why I didn't include that. Thanks, Richard
