diff --git a/core/vm/analysis.go b/core/vm/analysis.go
index 1640483b5096a..38b95b077c9c4 100644
--- a/core/vm/analysis.go
+++ b/core/vm/analysis.go
@@ -91,10 +91,10 @@ func codeBitmapInternal(code, bits bitvec) bitvec {
 				bits.set16(pc)
 				pc += 16
 				numbits -= 16
-				if numbits >= 16 {
+				if numbits == 16 {
 					bits.set16(pc)
 					pc += 16
-					numbits -= 16
+					numbits = 0
 				}
 			}
 			if numbits >= 8 {