On Thu, 23 Feb 2006, Chris Emerson wrote:

> On Wed, Feb 22, 2006 at 10:41:34AM -0700, Bob Axtell wrote:
>> Spehro has it right- to use the code access capability of the
>> F877 allows the LUT to handle all of it, i.e. 2 bits for 100s, 4
>> bits for tens, 4-bits for ones places, a total of 10 bits. BUT, it uses
>> over 260 code words. Would run about 9 cycles to extract a
>> lookup value, however, faster than my earlier suggestion.
>
> As a compromise you could save about half that space (at the cost of a
> few cycles) by first right-shifting, dividing by 5 using a half-size
> LUT, and adding the LSB back into the remainder at the end.

N/10 = N/8 - N/32 + N/128 ( - N/640 ... )

The terms before the parentheses are enough for 8 bits.

Peter
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist