diff --git a/src/include/86box/vid_8514a.h b/src/include/86box/vid_8514a.h
index af46b166d..0bb1e85cd 100644
--- a/src/include/86box/vid_8514a.h
+++ b/src/include/86box/vid_8514a.h
@@ -63,8 +63,9 @@ typedef struct ibm8514_t
         int sys_cnt, sys_cnt2;
         int temp_cnt;
         int16_t cx, cy;
-        int sx, sy;
-        int dx, dy;
+        int16_t sx, sy;
+        int16_t dx, dy;
+        int16_t err;
         uint32_t src, dest;
         uint32_t newsrc_blt, newdest_blt;
         uint32_t newdest_in, newdest_out;