Re: Signed integer to modular type conversion

[adam@irvine.com (Adam Beneschan)]

dewar@gnat.com (Robert Dewar) wrote in message news:<5ee5b646.0205160153.75230135@posting.google.com>...
> adam@irvine.com (Adam Beneschan) wrote in message news:<b4682ab7.0205151602.3c564c9e@posting.google.com>...
> 
> 
> > Would you still use something like Z := X + ToModType(Y) [where
> > ToModType is an instance of Unchecked_Conversion]?
> 
> No, I would use a 64-bit type to compute. If you have a deficient
> compiler that does not support 64-bit integers, then you have trouble,
> but so what? You could have equally asked to deal with numbers in the
> range 2**44, and then you would have needed a larger type anyway.
> 
> These days, all compilers should support 64-bit integers.

If the compiler supports 64-bit integers, then change my question so
that I have a number in the range 0..2**64-1 and a number in the range
-2**63 to 2**63-1 and wish to add them.  Now my question still stands.
 (Unless you want to answer by saying that these days all compilers
should support 128-bit integers.)

				-- Adam