[fpc-devel] softfloat: sizeOf( floatx80 )

[Martin Frb]

On 28/09/2024 09:34, Pierre Muller via fpc-devel wrote:
> I think that the big endian version (see grep below)
> would suffer if you would use packed
> because the high field of size 2,
> would put the low field of size 8 at offset 2,
> which would trigger unaligned access to this field.
>
> For the little endian definition,
> it doesn't change anything, does it?

It's not to important (for my case ).
I have a case where the data comes from another process (just 10 bytes, 
that are an extended in a 32bit process (Win), and get loaded by a 64bit 
process into the softfloat.)

I was comparing; SizeOf(MyVAr) = 10
and that failed.
So now I had to hardcode everywhere that a floatx80 can take those 10 bytes.

If I had wanted to put that in a generic and specialize with floatx80, 
double and single, then I had a problem because sizeOf would not work. I 
don't currently need it as generic.


About the big endian issue: That means it is not memory compatible with 
a native "extended" because it has a gap. So if you load data from a 
file/stream that has been written with native (gap free) extended, then 
it wont work.

I don't know if floatx80 promises such compatibility. But it would be 
very useful if it did.
On little endian, tests have shown that it can be used that way.