On Tue, Oct 28, 2008 at 08:55:59PM +0100, Henning Thielemann wrote: >> For example, is integer arithmetic faster or slower than >> floating-point? > > In principle integer arithmetic is simpler and faster. But your > processor may do it in the same time.
Indeed. Usually there are more integer arithmetic units, so more integer arithmetic can be done in parallel. >> Is addition faster or slower than multiplication? > > Multiplication can be done almost as fast as addition. This is so, > because a sum of n numbers can be computed much faster than n individual > additions. > >> How much slower are the trigonometric functions? > > division, square root are similar in complexity. exp, log, arctan can be > implemented with a school division like algorithm (CORDIC) and are > similar in performance. Last I looked (which was quite a while back, but considerably more recent than the 68k or Z80...), floating point division was the surprise slow operation (close to the cost of a transcendental), with square root being 5-10 times faster. Generally, floating point multiplies and adds have a throughput of 1 or 2 per clock cycle, with most modern processors having a fused mutliply-add. It does pay to reduce the number of divides and floating point operations... but probably not if you're writing in Haskell. :) David _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
