[Fwd: Re: [avr-gcc-list] maga256 patch for GCC 4.2]

[Harald Kipp]

Anatoly asked me to forward this to the list:


On Thu, 03 May 2007 11:17:33 +0200
Harald Kipp <address@hidden> wrote:
> Anatoly,
>
> I understood your arguments against taking main() as a 
> normal function. But I do not understand...
>
> 1. ...why this implies to modify the stack pointer on 
> entry. This spoils any the stack pointer modification in 
> the .init segment.

In begining of 'main'  function stack pointer should be 
modifed for reservation of space for  'main'  local 
variables in stack. Modification of stack pointer can be 
excluded only if  'main' don't have local variables.

Patch: "optimize_main_prologue.diff" in savannah bug 
record #19050.
http://savannah.nongnu.org/bugs/download.php?file_id=11990

> 2. ...your statement about "In oficial GCC 4.x main() do 
> not converted to a normal function." I'm sure that in 
> official GCC main() is always a subroutine and always 
> returns an int.

No. Oficial GCC jump to main.


Anatoly.