Hi Peter.

Peter wrote:
> 
> You can think of your numbers as fixed point. This implies especially
> that the precision is limited. So to convert, you can figure in a fixed
> multiplier, eg:
> 
> xx.yy  = 0XXYY/100 -> you store 0XXYY 2
> xxx.yy = XXXYY/100 -> you store XXXYY 2
> xx     = 0XX00/100 -> you store 0XX00 0
> x.y    = 00XY0/100 -> you store 00XY0 1

Isn't that supposed to be ( last two )

xx     = 000XX/100 -> you store 000XX 0
x.y    = 000XY/100 -> you store 000XY 1

Or in your terms

xx     = 0XX00/100 -> you store 0XX00 2
x.y    = 00XY0/100 -> you store 00XY0 2


Dmitriy.



> thus the decimal point 'disappears' for internal conversion and
> comparison purposes (you store 0XXYY), but you store is away and use it
> later for display. You have to store the requested precision (number of
> digits after . entered) along with the encoded request. Then when you
> display a number you do:
> 
> 0XXYY 1 -> zXX.Y
> 
> z is a suppressed leading zero, XX are the integer part, you print a dot
> iff the original string had a dot, and as many Y's as Y's were in the
> original string after the dot (and suppress the others).
> 
> To store and compare data easily in internal form you can use the binary
> form of XXXYY. Multiplying binary values by d'100' is easy (as long as
> you do not ever need to divide). If you have enough storage you can use
> the decimal form (f.ex. unpacked BCD) for arithmetics. This makes for
> low cost conversion for display on multiplier-less micros.
> 
> I hope that this makes sense. It's 3AM here.
> 
> Peter
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist