diff --git a/src/utils.h b/src/utils.h
new file mode 100644
index 0000000..f948620
--- /dev/null
+++ b/src/utils.h
@@ -0,0 +1,16 @@
+#ifndef _UTILS_H
+#define _UTILS_H
+
+#define DECR(x,n) x-=n
+#define INCR(x,n) x+=n
+
+#ifndef MAX
+#define MAX(a,b) (a>b?a:b)
+#endif
+#ifndef MIN
+#define MIN(a,b) (a<b?a:b)
+#endif
+
+// in error.c!
+void error(reg_t *R,error_t e);
+#endif