lkml.org 
[lkml]   [2018]   [May]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 2/2] mtd: rawnand: use bit-wise majority to recover the contents of ONFI parameter
On Tue, 15 May 2018 10:46:00 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Tue, May 15, 2018 at 10:35 AM, Boris Brezillon
> <boris.brezillon@bootlin.com> wrote:
> > On Mon, 14 May 2018 20:54:36 +0300
> > Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> >
> >> On Thu, May 10, 2018 at 3:03 PM, Boris Brezillon
> >> <boris.brezillon@bootlin.com> wrote:
> >>
> >> >> +#define GET_BIT(bit, val) (((val) >> (bit)) & 0x01)
> >> >
> >> > Not sure we need that macro, see below.
> >>
> >> +1. We have too many nice helpers for bit manipulations
> >> (for_each_set_bit() as an example).
> >>
> >>
> >> > for (k = 0; k < nbufs; k++) {
> >> > const u8 *srcbuf = srcbufs[j];
> >> >
> >> > if (srcbuf[i] & BIT(k))
> >> > m++;
> >> > }
> >>
> >> ...which is effectively hweightXX().
> >
> > No it's not.
>
> I don't see how "not". In the loop everithing except m and k are
> invariants. What did I miss?

We're not counting the number of bits set in an uXX var, but the number
of set bits at the same position in different buffers.

>
> The powerness of two of nbufs is another thing of _existing_
> prototypes of hweightXX().
>

\
 
 \ /
  Last update: 2018-05-15 10:04    [W:0.200 / U:2.308 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site