a style question

Chris Torek chris at mimsy.umd.edu
Mon Oct 1 19:57:47 AEST 1990


[on the test `x < 100' vs `x != 100' in a for loop]

In article <DAVIS.90Oct1025438 at pacific.mps.ohio-state.edu>
davis at pacific.mps.ohio-state.edu ("John E. Davis") writes:
>Which generates faster code?  It seems to me that it is easier to tell if
>two values are unequal than to tell if one is greater than the other.

Not really.  The easy comparisons are against 0; the others are generally
a bit harder.  (A comparison for `x == y' can be done in more ways than
one for `x < y', but this is not much of a recommendation.)  Look at the
test instructions on the current crop of fast CPUs for a demonstration.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 405 2750)
Domain:	chris at cs.umd.edu	Path:	uunet!mimsy!chris



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