Registers on the VAX 11/780?

Dave W. Smith dws at tolerant.UUCP
Sat Jul 20 04:11:19 AEST 1985


> >>... but how many register variables can I declare in a function on
> >>the VAX 11/780?
> 
> In probably all the PCC derived Vax C compilers, the number is 6,
> not 5.

A little known fact about PCC based C compilers is that you can recycle
registers with a function by using nested scopes.  Example (for 11/780):

	f()
	{ register int foo;		/* r11 */

	    { register int bar;		/* r10 */
		...
	    }

	    { register int baz;		/* r10 */
		...
	    }
	}
-- 
  David W. Smith             {ucbvax}!tolerant!dws
  Tolerant Systems, Inc.
  408/946-5667



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