1 files changed, 24 insertions, 0 deletions
diff --git a/euclid.h b/euclid.h
new file mode 100644
index 0000000..82fca4e
--- /dev/null
+++ b/euclid.h
@@ -0,0 +1,24 @@
+#ifndef EUCLID_H
+# define EUCLID_H 1
+
+# include "c23-fallback.h"
+# include <stdio.h>
+# include <assert.h>
+
+inline size_t gcd2(size_t a, size_t b) [[__unsequenced__]] {
+  assert(a <= b);                 /*@\label{gcd2-precondition}*/
+  if (!a) return b;               /*@\label{gcd2-bottom}*/
+  size_t rem = b % a;             /*@\label{gcd2-remainder}*/
+  return gcd2(rem, a);            /*@\label{gcd2-recurse}*/
+}
+
+inline size_t gcd(size_t a, size_t b) [[__unsequenced__]] {
+  assert(a);
+  assert(b);
+  if (a < b)
+    return gcd2(a, b);
+  else
+    return gcd2(b, a);
+}
+
+#endif