diff --git a/obj/tools/lisp/stack.h b/obj/tools/lisp/stack.h
new file mode 100644
index 0000000..f0578f4
--- /dev/null
+++ b/obj/tools/lisp/stack.h
@@ -0,0 +1,8 @@
+// STACK.H -- stack macros
+
+#define INITSTACK(s)	(s = ({}))
+#define PUSH(s,x)	(s += ({ (x) }))
+#define POP(s,x)	(x = s[<1], s = s[0..<2])
+#define POPX(s)		(s = s[0..<2])
+#define TOP(s)		((s)[<1])
+#define SP(s)		(sizeof(s))