Standard'Maximum_Alignment

Standard'Maximum_Alignment

[jan.de.kruyf]

Hallo,

Does anybody know about the history of this thing.


I get an error when I compile with the standard switches for making linux kernel modules.
------------------
gnat1: error: -mpreferred-stack-boundary=3 is not between 4 and 12
------------------

I think it clashes with 
-------
for Memory'Alignment use Standard'Maximum_Alignment;
--------
in s-memory.adb

according to this email Standard'Maximum_Alignment should be 16 which works out to a preferred-stack-boundary=4

https://gcc.gnu.org/ml/gcc-patches/2005-03/msg01456.html
--

gcc:
-mpreferred-stack-boundary=num
Attempt to keep the stack boundary aligned to a 2 raised to num byte boundary. If `-mpreferred-stack-boundary' is not specified, the default is 4 (16 bytes or 128 bits).
--

Am I right in  my assumption that kernel uses the value of 3 since none of the fancy cpu extensions are used in kernel code?

And gnat of course knows nothing about kernelcode. with or without the kernelcode switch it asks for memory with '__gnat_malloc'

Thanks,

j.

Re: Standard'Maximum_Alignment

[Simon Wright]

jan.de.kruyf@gmail.com writes:

> And gnat of course knows nothing about kernelcode. with or without the
> kernelcode switch it asks for memory with '__gnat_malloc'

You'd need to supply your own version of System.Memory.

Re: Standard'Maximum_Alignment

[jan.de.kruyf]

On Friday, May 29, 2015 at 2:22:47 PM UTC+2, Simon Wright wrote:

> 
> > And gnat of course knows nothing about kernelcode. with or without the
> > kernelcode switch it asks for memory with '__gnat_malloc'
> 
> You'd need to supply your own version of System.Memory.

I did, and that is where this error came in.
But I am not going to waste tons of memory so I can live with a courser alignment.

It was just puzzling at first.

j.