From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Subject: Re: [PATCH 57/89] drm/i915: Rewrite ABS_DIFF() in a safer manner Date: Thu, 04 Sep 2014 15:11:24 +0300 Message-ID: <874mwnfuvn.fsf@intel.com> References: <1409830075-11139-1-git-send-email-damien.lespiau@intel.com> <1409830075-11139-58-git-send-email-damien.lespiau@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id BAEBD6E5F4 for ; Thu, 4 Sep 2014 05:11:26 -0700 (PDT) In-Reply-To: <1409830075-11139-58-git-send-email-damien.lespiau@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Damien Lespiau , intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Thu, 04 Sep 2014, Damien Lespiau wrote: > The new version of the macro does a few things better: > - protect the arguments, > - only evaluate the arguments once, > - check that the arguments are of the same type, > > Change LC_FREQ_2K to be a unsigned 64bit constant and removed the '()' > from the caller as a result. > > Signed-off-by: Damien Lespiau Reviewed-by: Jani Nikula Can be picked up for dinq separate from this series, right? > --- > drivers/gpu/drm/i915/intel_ddi.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c > index 64eda53..ba1103f 100644 > --- a/drivers/gpu/drm/i915/intel_ddi.c > +++ b/drivers/gpu/drm/i915/intel_ddi.c > @@ -460,7 +460,7 @@ intel_ddi_get_crtc_encoder(struct drm_crtc *crtc) > } > > #define LC_FREQ 2700 > -#define LC_FREQ_2K (LC_FREQ * 2000) > +#define LC_FREQ_2K U64_C(LC_FREQ * 2000) > > #define P_MIN 2 > #define P_MAX 64 > @@ -472,7 +472,11 @@ intel_ddi_get_crtc_encoder(struct drm_crtc *crtc) > #define VCO_MIN 2400 > #define VCO_MAX 4800 > > -#define ABS_DIFF(a, b) ((a > b) ? (a - b) : (b - a)) > +#define abs_diff(a, b) ({ \ > + typeof(a) __a = (a); \ > + typeof(b) __b = (b); \ > + (void) (&__a == &__b); \ > + __a > __b ? (__a - __b) : (__b - __a); }) > > struct wrpll_rnp { > unsigned p, n2, r2; > @@ -582,9 +586,9 @@ static void wrpll_update_rnp(uint64_t freq2k, unsigned budget, > */ > a = freq2k * budget * p * r2; > b = freq2k * budget * best->p * best->r2; > - diff = ABS_DIFF((freq2k * p * r2), (LC_FREQ_2K * n2)); > - diff_best = ABS_DIFF((freq2k * best->p * best->r2), > - (LC_FREQ_2K * best->n2)); > + diff = abs_diff(freq2k * p * r2, LC_FREQ_2K * n2); > + diff_best = abs_diff(freq2k * best->p * best->r2, > + LC_FREQ_2K * best->n2); > c = 1000000 * diff; > d = 1000000 * diff_best; > > -- > 1.8.3.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center