[fpc-devel] State of SSE/AVX intrinsics

[Sven Barth]

denisgolovan via fpc-devel <fpc-devel at lists.freepascal.org> schrieb am Di.,
21. Apr. 2020, 13:32:

>
>
> > One thing to be slightly aware of with
> > dynamic pointers and alignment. For V: atray
> > of Integer etc, make sure you check the
> > alignment of V[0], not V. V points to an
> > internal structure that is largely opaque,
> > while V[0] points to the actual data, which I
> > imagine is what you want to pass into VMOVAPS
> > etc.
> >
> > Gareth aka. Kit
>
> I believe your are wrong here.
> For dynamic arrays, service data is located at negative offset and pointer
> itself _is_ zero element address.
>
> type
>    TIntArray = array of Integer;
>
> var v:TIntArray;
> begin
>    SetLength(v,100);
>    Writeln(NativeInt(Pointer(v)) = NativeInt(Pointer(@v[0]))); // always
> gives true
> end.
>

I think Gareth meant the address of V instead (Pointer(@V)).

Regards,
Sven

>
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