dix: fix warning in pointer acceleration

newer gcc's warn against how this cast is done (though it eludes me why),
and lrintf() is also faster especially on insane processors like the P4
(http://www.mega-nerd.com/FPcast).

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 8 insertions, 2 deletions

diff --git a/dix/ptrveloc.c b/dix/ptrveloc.c
index 1590cfdbf..7c49cf5cb 100644
--- a/dix/ptrveloc.c
+++ b/dix/ptrveloc.c
@@ -988,14 +988,20 @@ acceleratePointerPredictable(
 
                 if (dx) {
                     tmp = mult * fdx + pDev->last.remainder[0];
-                    *px = (int)roundf(tmp);
+                    /* Since it may not be apparent: lrintf() does not offer
+                     * strong statements about rounding; however because we
+                     * process each axis conditionally, there's no danger
+                     * of a toggling remainder. Its lack of guarantees hopefully
+                     * makes it faster on the average target. */
+                    *px = lrintf(tmp);
                     pDev->last.remainder[0] = tmp - (float)*px;
                 }
                 if (dy) {
                     tmp = mult * fdy + pDev->last.remainder[1];
-                    *py = (int)roundf(tmp);
+                    *py = lrintf(tmp);
                     pDev->last.remainder[1] = tmp - (float)*py;
                 }
+                DebugAccelF("pos (%i | %i) remainders x: %.3f y: %.3f delta x:%.3f y:%.3f\n", *px, *py, pDev->last.remainder[0], pDev->last.remainder[1], fdx, fdy);
             }
         }
     }