diff --git a/x86_64/machine.m4 b/x86_64/machine.m4
new file mode 100644
index 0000000000000000000000000000000000000000..887bf3b3a7a9fe849a05add58040e938733e0bf0
--- /dev/null
+++ b/x86_64/machine.m4
@@ -0,0 +1,3 @@
+C OFFSET(i)
+C Expands to 4*i, or to the empty string if i is zero
+define(<OFFSET>, <ifelse($1,0,,eval(4*$1))>)