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From: Michael Buesch <mb@bu3sch.de>
To: Pavel Roskin <proski@gnu.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>,
	John W Linville <linville@tuxdriver.com>,
	bcm43xx-dev@lists.berlios.de, linux-wireless@vger.kernel.org
Subject: Re: [PATCH] b43: Fix sparse warnings
Date: Sat, 15 Aug 2009 12:08:01 +0200	[thread overview]
Message-ID: <200908151208.01349.mb@bu3sch.de> (raw)
In-Reply-To: <1250286414.8137.55.camel@mj>

On Friday 14 August 2009 23:46:54 Pavel Roskin wrote:
> On Fri, 2009-08-14 at 17:29 -0400, Pavel Roskin wrote:
> > On Fri, 2009-08-14 at 23:00 +0200, Michael Buesch wrote:
> > > On Friday 14 August 2009 22:52:13 Pavel Roskin wrote:
> > > > On Fri, 2009-08-14 at 22:15 +0200, Michael Buesch wrote:
> > > > 
> > > > > > -			b43_phy_mask(dev, 0x048A, (u16)~0x8000);
> > > > > > +			b43_phy_mask(dev, 0x048A, (u16)(~0x8000 & 0xFFFF));
> > > > > 
> > > 
> > > > I would just use 0x7fff here.
> > > 
> > > That does not work if 0x8000 is a #defined bit.
> > 
> > One approach would be to use a macro and tell sparse to ignore it
> > 
> > #define NEGATE(x) (__force typeof(x))(~x)
> 
> Scratch that.  It has no change to work for constants unless we hardcode
> the size, e.g. by having NEGATE16, NEGATE32 etc.
> 
> The best I could do is:
> 
> #define NEGATE16(x) (0xFFFF & ~x)
> b43_phy_mask(dev, 0x048A, NEGATE16(0x8000));

I think the real question is whether this does really prevent any bugs or whether
it just introduces new possibilities for bugs.

void my_func(u32 x);

my_func(NEGATE16(0x8000));

-- 
Greetings, Michael.

  reply	other threads:[~2009-08-15 10:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-13 22:15 [PATCH] b43: Fix sparse warnings Larry Finger
2009-08-14 20:15 ` Michael Buesch
2009-08-14 20:52   ` Pavel Roskin
2009-08-14 21:00     ` Michael Buesch
2009-08-14 21:04       ` Gábor Stefanik
2009-08-14 21:35         ` Pavel Roskin
2009-08-15 10:04           ` Michael Buesch
2009-08-17 20:30             ` Pavel Roskin
2009-08-18 13:12               ` Michael Buesch
2009-08-14 21:29       ` Pavel Roskin
2009-08-14 21:46         ` Pavel Roskin
2009-08-15 10:08           ` Michael Buesch [this message]
2009-08-14 21:33   ` Larry Finger
  -- strict thread matches above, loose matches on Subject: below --
2007-09-19 16:30 Michael Buesch

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