On Wed, Feb 08, 2012 at 09:10:51PM +0100, Chase Douglas wrote: > On 02/08/2012 03:54 PM, Peter Hutterer wrote: > > On Tue, Feb 07, 2012 at 01:07:08PM -0800, Chase Douglas wrote: > >> Signed-off-by: Chase Douglas <[email protected]> > >> --- > >> src/synaptics.c | 2 +- > >> 1 files changed, 1 insertions(+), 1 deletions(-) > >> > >> diff --git a/src/synaptics.c b/src/synaptics.c > >> index a4c1e5a..106b5ee 100644 > >> --- a/src/synaptics.c > >> +++ b/src/synaptics.c > >> @@ -1791,7 +1791,7 @@ HandleTapProcessing(SynapticsPrivate *priv, struct > >> SynapticsHwState *hw, > >> } > >> > >> #define HIST(a) (priv->move_hist[((priv->hist_index - (a) + > >> SYNAPTICS_MOVE_HISTORY) % SYNAPTICS_MOVE_HISTORY)]) > >> -#define HIST_DELTA(a, b, e) ((HIST((a)).e) - (HIST((b)).e)) > >> +#define HIST_DELTA(a, b, e) ((int)((HIST((a)).e) - (HIST((b)).e))) > > > > this only casts the result to a signed int, the actual computation is still > > undefined for b > a. With the revert, HIST_DELTA is only used in one place > > so we could either do it there or just write a helper function like this > > Why is it undefined? We can have a negative time difference, which is > what the calculation was assuming, IIUC.
yeah, but IIRC (unsigned int)a - (unsigned int)b is undefined for b > a. Cheers, Peter _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
