[fpc-devel] Question on updating FPC packages

Florian Klämpfl florian at freepascal.org
Sun Oct 27 09:02:54 CET 2019

Am 27.10.19 um 07:32 schrieb J. Gareth Moreton:
> I guess you're right.  It just seems weird because the System V ABI was 
> designed from the start to use the MM registers fully, so long as the 
> data is aligned.  In effect, it had vectorcall wrapped into its design 
> from the start.  Granted, vectorcall has some advantages and can deal 
> with relatively complex aggregates that the System V ABI cannot handle 
> (for example, a record type that contains a normal vector and 
> information relating to bump mapping).
> I just hoped that making updates to uComplex, while ensuring existing 
> Pascal code still compiles, would help take advantage of modern ABI designs.

Is there currently any example which shows that vectorcall has any 
advantage with FPC? Else I would propose first to make FPC able to take 
advantage of it and then talk about if we really add vectorcall. 
Currently I fear, FPC gets only into trouble when using vectorcall as it 
tries first to push everything into one xmm register and then splits 
this again in the callee.

More information about the fpc-devel mailing list