At 01:04 PM 2/26/98 -0800, you wrote:
>>>On 23 Feb, jhobbs wrote:
>>/I once knew a fast trick for divide by 3, but now I am unable to reproduce
>>>/it.  If someone can share it with me (and others) that would be great.
>>>/
>>>/Take care -Jim
>
>>>    Simple.  To multiply by 3, double and add to original.  To divide by 3,
>>>just do the inverse!
>>>-- Mel Evans
>
>>Could someone unfold that for a binary math newbie, please?
>>/Morgan
>>/  Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \ \
>>mrt@iname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331    /
>
>Sure.
>
>Let's start with the number 5. In binary that is:
>
> 101
>
>Since the place value of binary is two, you can double the number by
shifting it
>left one bit, like this:
>
>Old:  101
>New: 1010
>
>Now you add it to the original number, like this
>
>
>     1010
>   +  101
>   ------
>     1111
>
>The result is the number 15, which is the answer to 5 * 3!
>
>
>Later,
>
>Eric
>

Yeah, fine for multiplication, but that neat relationship doesn't hold for
division, at least as far as I can see. Take 10/3 for example:

10 shifted down one is 5

now, what can you do to 5 to get 3.3333?

It seems to me that Andy Warren had the best solution, do a series of
divisions by powers of two until you get the accuracy you need.

Sean

+--------------------------------+
| Sean Breheny                   |
| Amateur Radio Callsign: KA3YXM |
| Electrical Engineering Student |
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