On Wed, 31 May 2023, Shaopeng Tan (Fujitsu) wrote:
> Hi Ilpo,
>
> > CAT and CMT tests depends on masks being continuous.
> >
> > Replace count_bits with more appropriate variant that counts consecutive bits.
> >
> > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> > ---
> > @@ -218,6 +220,34 @@ static int get_bit_mask(char *filename, unsigned long
> > *mask)
> > return 0;
> > }
> >
> > +/*
> > + * count_consecutive_bits - Returns the longest train of bits in a bit mask
> > + * @val A bit mask
> > + * @start The location of the least-significant bit of the longest train
> > + *
> > + * Return: The length of the consecutive bits in the longest train of bits
> > + */
> > +unsigned int count_consecutive_bits(unsigned long val, unsigned int
> > +*start) {
> > + unsigned long last_val;
> > + int count = 0;
> > +
> > + while (val) {
> > + last_val = val;
> > + val &= (val >> 1);
> > + count++;
> > + }
>
> There may not be a case that the most-significant bit is 1 at present,
> but if this case exists, it cannot count correctly.
Can you please rephrase what is your concern here please?
I test 0U, 1U, ~0U, and a few more complex combinations of bits, and all
returned correct count so I might not have understood what case you meant
with your description.
This function does not count nor calculate the most-significant bit in
any phase but the longest train of bits using the count variable (and the
least-significant bit of the longest train in the code that is not
included into this partial snippet).
--
i.
