[PATCH] Document arithmetic overflow semantics

[Andrew Haley]

Robert Dewar writes:
 > > Java requires strict 32-bit two's complement arithmetic for its ints,
 > > and PLUS_EXPR isn't guaranteed to do that.  We could, of course,
 > > generate something like
 > > 
 > >    uint((ulong)a + (ulong)b)
 > > 
 > > which would be well defined. 
 > 
 > it seems clear that Java should be using unsigned arithmetic for all operations,
 > since that is the way Java is defined.

What do you mean by this, exactly?  Java is defied as having signed
two's complement arithmetic.

Andrew.