On Wed, Jun 24, 2020 at 10:30:18AM +0200, Thomas Monjalon wrote:
> 24/06/2020 10:24, Harman Kalra:
> > On Wed, Jun 24, 2020 at 10:13:18AM +0200, Thomas Monjalon wrote:
> > > 09/06/2020 21:17, Harman Kalra:
> > > > Found an issue while using RTE_ALIGN_MUL_NEAR with an
> > > > expression, like as passed in estimate_tsc_freq().
> > > > RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
> > > > above function as division has more precedence over
> > > > substraction.
> > >
> > > The only change I see is adding parenthesis around v.
> > > Am I right?
> >
> > Yes, parathesis are required if an expression is passed.
>
> I think the commit log needs to be updated.
> I don't see the relation between
> "division has more precedence over substraction"
> and
> "parathesis are required if an expression is passed"
By "division has more precedence over substraction", I tried to
highlight the issue which resulted in unexpected value, but yes
it is sounding confusing. I will reword the commit message and send
V2.
>
>
> > > > #define RTE_ALIGN_MUL_CEIL(v, mul) \
> > > > - (((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) *
> > > > (typeof(v))(mul))
> > > > + ((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) *
> > > > (typeof(v))(mul))
> > > [...]
> > > > #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> > > > - ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > > + (((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > [...]
> > > > ({ \
> > > > typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
> > > > typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
> > > > - (ceil - v) > (v - floor) ? floor : ceil; \
> > > > + (ceil - (v)) > ((v) - floor) ? floor : ceil; \
> > > > })
> > >
> > >
> > >
> > >
> >
>
>
>
>
>
