From 2ca6aa4910efcfa5dc4d0e8661d3a74eac28a727 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 5 Jan 2021 18:39:36 -0800
Subject: [PATCH] Initial file

---
 ck-polyfill.c | 28 ++++++++++++++++++++++++++++
 ck_pr.h       |  9 +++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 ck-polyfill.c
 create mode 100644 ck_pr.h

diff --git a/ck-polyfill.c b/ck-polyfill.c
new file mode 100644
index 00000000..3ba00187
--- /dev/null
+++ b/ck-polyfill.c
@@ -0,0 +1,28 @@
+/** 
+ * Cyclone Scheme
+ * https://github.com/justinethier/cyclone
+ *
+ * Copyright (c) 2020, Justin Ethier
+ * All rights reserved.
+ *
+ * FFI module to support calling Scheme code from C.
+ */
+
+#include "cyclone/types.h"
+#include "cyclone/runtime.h"
+#include <ck_pr.h>
+#include <unistd.h>
+
+// TODO: global pthread mutex lock for this? obviously not ideal but the
+// whole purpose of this module is a minimal interface for compatibility
+// not speed
+
+bool
+ck_pr_cas_int(int *target, int old_value, int new_value)
+{
+  if (*target == old_value) {
+    *target = new_value;
+    return true;
+  }
+  return false;
+}
diff --git a/ck_pr.h b/ck_pr.h
new file mode 100644
index 00000000..0075fbce
--- /dev/null
+++ b/ck_pr.h
@@ -0,0 +1,9 @@
+#ifndef CYCLONE_CK_POLYFILL_H
+#define CYCLONE_CK_POLYFILL_H
+
+#include <stdbool.h>
+
+ bool
+ ck_pr_cas_int(int *target, int old_value, int new_value);
+
+#endif                          /* CYCLONE_CK_POLYFILL_H */