diff --git a/a8/sysutils.cc b/a8/sysutils.cc
index 038a4be..c3cd3d8 100644
--- a/a8/sysutils.cc
+++ b/a8/sysutils.cc
@@ -110,6 +110,11 @@ namespace a8
         return (flag_bits & ((long long)1 << bit)) != 0;
     }
 
+    bool SameBitFlag(long long a_flag_bits, long long b_flag_bits, int bit)
+    {
+        return HasBitFlag(a_flag_bits, bit) == HasBitFlag(b_flag_bits, bit);
+    }
+
     void XPrintf(const char* fmt, std::initializer_list<a8::XValue> args)
     {
         time_t nowtime = time(nullptr);
diff --git a/a8/sysutils.h b/a8/sysutils.h
index cb6cf7a..140bfd1 100644
--- a/a8/sysutils.h
+++ b/a8/sysutils.h
@@ -71,6 +71,7 @@ namespace a8
     void SetBitFlag(long long& flag_bits, int bit);
     void UnSetBitFlag(long long& flag_bits, int bit);
     bool HasBitFlag(const long long& flag_bits, int bit);
+    bool SameBitFlag(long long a_flag_bits, long long b_flag_bits, int bit);
     void XPrintf(const char* fmt, std::initializer_list<a8::XValue> args);
     bool MkDir(const std::string& path);
     void ForceCreateDir(const std::string& path);