diff --git a/lib/std/sort/countingsort.c3 b/lib/std/sort/countingsort.c3
index 19c2836fd..864cb9276 100644
--- a/lib/std/sort/countingsort.c3
+++ b/lib/std/sort/countingsort.c3
@@ -26,8 +26,8 @@ macro quicksort_indexed(list, start, end, cmp = EMPTY_MACRO_SLOT, context = EMPT
 
 module std::sort::cs(<Type, KeyFn>);
 
-def Counts = ulong[256] @private;
-def Ranges = ulong[257] @private;
+def Counts = usz[256] @private;
+def Ranges = usz[257] @private;
 def Indexs = char[256] @private;
 def ElementType = $typeof(Type{}[0]);
 
@@ -107,11 +107,14 @@ fn void csort(Type list, usz low, usz high, KeyFn key_fn, uint byte_idx)
 		total += count;
 	}
 	ranges[256] = total;
-
-	for(ushort i = 0; i < 256; i++) {
+	
+	ushort remaining_indexs = 256 - (fallback0_count + recursion_count);
+	for(ushort i = 0; (i < 256) && remaining_indexs; i++) {
 		indexs[fallback0_count + fallback1_count] = (char)i;
-		ushort count = ranges[i + 1] - ranges[i];
-		fallback1_count += (ushort)(count > 32 && count <= 128);
+		usz count = ranges[i + 1] - ranges[i];
+		ushort within_fallback1_range = (ushort)(count > 32 && count <= 128);
+		fallback1_count += within_fallback1_range;
+		remaining_indexs -= within_fallback1_range;
 	}
 	
 	if (!keys_ordered)