On Wed, Aug 16, 2000 at 12:02:03PM +0300, Jukka Marin wrote:
> > That's not so easy. The fix is to use floating point values for the
> > intermediary result. And I can't do that of course inside the kernel.
> 
> How about using 32-bit integers with 16 bits as integer part and 16 bits
> of fraction?  Multiply (shift left) the incoming byte (or 16-bit word,
> if necessary) value and store the result.. and convert back when necessary.

I found an easier way already:

#define TO_OSSVOL(x) ((((x) * 200 / 255) + 1) >> 1)
#define FROM_OSSVOL(x) (((((x) > 100 ? 100 : (x)) * 510 / 100) + 1) >> 1)

It uses one extra bit of precision which is enough for appropriate rounding.

	Kind regards

-- 
Matthias Scheler                            http://www.sighardstrasse.de/~tron/