RE: Supporting multiple pointer sizes in GCC

["Jayant R. Sonar" <Jayant.Sonar@kpitcummins.com>]

>?  MIPS has two pointer sizes, but a given compilation (gcc 
> invocation) uses only one of them, it comes from the chosen ABI.

Yes, it looks like MIPS have got 2 ABIs - 32bit and 64bit. The choice
of the ABI is controlled through a command line option '-march=arch'. 
Therefore in MIPS it doesn't look possible to have 2 pointers of 
different sizes existing simultaneously inside a single executable.

Whereas, what I am looking forward to do is adding some target 
specific data attributes, say data16 and data32. In a simple test case 
I should be able to declare two different pointer variables using these
attributes as following:

char * ptrABC __attribute__ (data16);
char * ptrXYZ __attribute__ (data32);

The size of ptrABC should be 16bits and that of ptrXYZ should 
be 32bits.

Will it be possible to do something like this in GCC?

Regards,
Jayant
 

-----Original Message-----
From: Paul Koning [mailto:paul_koning@dell.com] 
Sent: Friday, March 25, 2011 11:20 PM
To: DJ Delorie
Cc: Jayant R. Sonar; gcc@gcc.gnu.org
Subject: Re: Supporting multiple pointer sizes in GCC


On Mar 25, 2011, at 1:37 PM, DJ Delorie wrote:

> 
> "Jayant R. Sonar" <Jayant.Sonar@kpitcummins.com> writes:
>> Is it possible to support multiple pointer sizes (e.g. 16bit, 32bit)
>> which can co-exist in single compilation unit?
>> Whether it is supported in GCC now?
>> Is there any other architecture which has this feature already 
>> implemented?
> 
> Yes, there are three that I know of - mips64, s390 (tpf), and m32c.

?  MIPS has two pointer sizes, but a given compilation (gcc invocation) uses only one of them, it comes from the chosen ABI.

	paul