diff --git a/src/mesa/drivers/dri/r200/r200_state.c b/src/mesa/drivers/dri/r200/r200_state.c
index b75ff5c..41de6b0 100644
--- a/src/mesa/drivers/dri/r200/r200_state.c
+++ b/src/mesa/drivers/dri/r200/r200_state.c
@@ -1591,7 +1591,7 @@ void r200UpdateWindow( struct gl_context *ctx )
 
       /* add magic offsets, then invert */
       stx = 31 - ((-1) & R200_STIPPLE_COORD_MASK);
-      sty = 31 - ((yoffset - 1)
+      sty = 31 - (((int) yoffset - 1)
                   & R200_STIPPLE_COORD_MASK);
 
       m |= ((stx << R200_STIPPLE_X_OFFSET_SHIFT) |