diff --git a/os/zmath.cpp b/os/zmath.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/os/zmath.hpp b/os/zmath.hpp
new file mode 100644
index 0000000..5089e9b
--- /dev/null
+++ b/os/zmath.hpp
@@ -0,0 +1,8 @@
+#pragma once
+#include <stdbool.h>
+namespace iflytop {
+using namespace std;
+static inline float zfabs(float a) { return a > 0 ? a : -a; }
+static inline bool  zfeq(float a, float b, float eps) { return zfabs(a - b) < eps; }
+
+}  // namespace iflytop
\ No newline at end of file
diff --git a/os/zos.hpp b/os/zos.hpp
index 6f624cc..27e7091 100644
--- a/os/zos.hpp
+++ b/os/zos.hpp
@@ -15,6 +15,8 @@
 #include "zos_thread.hpp"
 //
 #include "zos_schduler.hpp"
+//
+#include "zmath.hpp"
 extern "C" {
 typedef struct {
   uint32_t __reserved0;