Re: Stack Allocations

[wwieser () gmx de]

On Monday 09 July 2001 15:27, msoda () aspre net wrote:
> Hey all,
<snip>
> When running 'gcc -S' it shows that 24 bytes are allocated on the stack
> for buf[].  I thought it should allocate only 16 bytes.  It works fine, it
> just makes no sense to me.  If I tweak the assembly and change it to 16
> bytes and also change the offsets to %ebp that reference it, it works fine
> also.
>
> Does anyone know why gcc does this?  My need to understand everything is
> killing me!
It's due to gcc's preferred stack boundary. Seems to be some sort of 
alignment issue. 
Simply do a 
bash# gcc  -mpreferred-stack-boundary=2 -S foo.c -o foo.s
and you get 16 bytes as expected. 

wwieser