diff --git a/XVim/NSTextStorage+VimOperation.m b/XVim/NSTextStorage+VimOperation.m
index 2214e9c3..87fda110 100644
--- a/XVim/NSTextStorage+VimOperation.m
+++ b/XVim/NSTextStorage+VimOperation.m
@@ -253,7 +253,7 @@ - (NSUInteger)xvim_firstOfLine:(NSUInteger)index
         return NSNotFound;
     }
 
-    if (pos == index && isNewline([self.xvim_string characterAtIndex:(pos - 1)])) {
+    if (pos == index && pos > 0 && isNewline([self.xvim_string characterAtIndex:(pos - 1)])) {
         return NSNotFound;
     }
     return pos;