Author: David Blackman
Date: 00:13:08 06/17/99
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On June 16, 1999 at 23:01:38, Dave Gomboc wrote: >On June 16, 1999 at 22:56:02, Greg Lazarou wrote: > >>Hi James, >> >>I don't have the straight answer to your question but if x is an integer then >>multiplications by 2 and divisions by 2 (the 4th and 2nd cases respectively) >>should be very fast left and right shifts. Now you can let the compiler figure >>it out (and you may be able to help the compiler figure it out by expressing >>x*=.5 as x /= 2) or you can code it as a shift yourself... > >N.B. (x /= 2) == (x >> 1) iff (x is unsigned) > >Dave But for signed numbers (x >> 1) is almost always what you really want. And if you want to divide by something other than a power of two you curse hardware and language designers for not making signed division work properly.
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