Data Type sizes question

Data Type sizes question

[John Lu]

Hi,

I'm working on an architecture that supports 16-bit,
32-bit, and 40-bit data.  I am trying to support the following data
types on the archtiecture:

	int		-> QImode, 16-bits
	long		-> HImode, 32-bits
	long long	-> SImode, 40-bits   ??????

These sizes were set by defining INT_TYPE_SIZE, LONG_TYPE_SIZE
and LONG_LONG_TYPE_SIZE appropriately.  Is this feasible with gcc?  
I have a compiler with just the 16-bit and 32-bit sizes working fine.  
When I try to add the "long long" type, the SImode instructions are 
used for 64-bit structures.  GCC seems to think that the SImode 
supports 64-bit data (which I guess is reasonable).  Is there a way
to prevent GCC from doing this?

Thanks,
John Lu

Re: Data Type sizes question

[Fergus Henderson]

On 28-Oct-2002, John Lu <jlu@lsil.com> wrote:
> I'm working on an architecture that supports 16-bit,
> 32-bit, and 40-bit data.  I am trying to support the following data
> types on the archtiecture:
> 
> 	int		-> QImode, 16-bits
> 	long		-> HImode, 32-bits
> 	long long	-> SImode, 40-bits   ??????

This is a bad idea.  The ISO C standard guarantees that "long long"
will be at least 64 bits.

-- 
Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.