Re: [Tinycc-devel] i386 Double alignment- bug?

[Mike Henning]

--- Daniel Glöckner <address@hidden> wrote:

> On Tue, Sep 19, 2006 at 09:56:17AM -0700, Mike
> Henning wrote:
> > I noticed that the sizeof a double is returned as
> 8,
> > which should be correct, but 4 is returned in
> align.
> 
> This is correct behaviour on x86 Linux.
> GCC has a command line switch to align doubles to 8
> bytes.
> 
> > #pragma pack(8)
> > typedef struct _foo
> > {
> > char    a;
> > int     v1;
> > int     v2;
> > double  d1;
> > }foo;
> > 
> > sizeof(foo) = 20 regardless of the pack value set.
> > Using the above example it should return 24.
> 
> No, it shouldn't.
> Pragma pack sets the maximum alignment as is
> described here:
>
http://msdn2.microsoft.com/en-us/library/2e70t5y1.aspx
> 
> Anyway, pragma pack is non-standard and TinyCC is
> allowed to do whatever
> it wants. It just so happens, that TinyCC behaves
> the same way MSVC does.
> 
> > So should align be returning 8 here?
> 
> Only if you are using TinyCC in Windows.
> 

Sorry, I should have mentioned that I'm working under
Windows. 

Maybe the this should be written as:

#if defined(TCC_TARGET_I386) && !defined(WIN32)
        *a = 4; 
#else
        *a = 8;
#endif
        return 8;


Thanks,
Mike H.


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