avcodec/cavsdec: simplify % 512 operations

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

diff --git a/libavcodec/cavsdec.c b/libavcodec/cavsdec.c
index 51f6e25d34f75a612da219242d560c646911c965..20cc18081ee091519e05cf601620e6d838408f28 100644 (file)
--- a/libavcodec/cavsdec.c
+++ b/libavcodec/cavsdec.c
@@ -1003,11 +1003,11 @@ static int decode_pic(AVSContext *h)
 
     /* get temporal distances and MV scaling factors */
     if (h->cur.f->pict_type != AV_PICTURE_TYPE_B) {
-        h->dist[0] = (h->cur.poc - h->DPB[0].poc  + 512) % 512;
+        h->dist[0] = (h->cur.poc - h->DPB[0].poc) & 511;
     } else {
-        h->dist[0] = (h->DPB[0].poc  - h->cur.poc + 512) % 512;
+        h->dist[0] = (h->DPB[0].poc  - h->cur.poc) & 511;
     }
-    h->dist[1] = (h->cur.poc - h->DPB[1].poc  + 512) % 512;
+    h->dist[1] = (h->cur.poc - h->DPB[1].poc) & 511;
     h->scale_den[0] = h->dist[0] ? 512/h->dist[0] : 0;
     h->scale_den[1] = h->dist[1] ? 512/h->dist[1] : 0;
     if (h->cur.f->pict_type == AV_PICTURE_TYPE_B) {