array[-1] -- permitted?

[Mark Jones]

In article <1988Sep19.164701.11136 at ateng.uucp>, chip at ateng.uucp (Chip Salzenberg) writes:
> According to news at ism780c.isc.com:
> >But consider what might have happened had dpANS mandated that the compution
> >of a pointer to x[-1] be a valid operation.
> 
> Okay, let's imagine:  X3J11 says that x[-1] must be valid.
> 	       then:  int must be 32 bits.

Excuse my ignorance, but why must an int be 32 bits for the above to work?

> 	       then:  address space must be linear.

Does X3J11 say that the contents of x[-1] must be valid?

Mark Jones