short circuit evaluation

[tim at amdcad.UUCP]

In article <5178 at mimsy.UUCP> chris at mimsy.UUCP (Chris Torek) writes:
	(OFF is all zeros, ON is all ones)
+---------------------------------------
|	&	1.  Left side evaluated.  If OFF, evaluation stops;
|		    result is OFF.  If not, right side evaluated,
|		    and both results ANDed.
|		2.  Left side evaluated.  Right side evaluated.
|		    Results ANDed.
|		3.  Right side evaluated.  If OFF, evaluation stops;
|		    result is OFF.  If not, left side evaluated, and
|		    both results ANDed.
|
|	|	1.  Left side evaluated.  If ON, evaluation stops;
|		    result is ON.  If not, right side evaluated,
|		    and both results ORed.
|		2.  Left side evaluated.  Right side evaluated.
|		    Results ORed.
|		3.  Right side evaluated.  If ON, evaluation stops;
|		    result is ON.  If not, left side evaluated, and
|		    both results ORed.
+---------------------------------------
What about if either the left side expression or the right side
expression contained a side-effect (or a procedure call, which also may
have a side-effect)?  These cannot be short-circuited when bit-wise
operators are used.

	-- Tim Olson
	Advanced Micro Devices

	"We plan products, not lunches"