From ddd057f97bd774571d460c6a46ea1d682689a9fa Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Thu, 30 May 2019 13:18:50 -0400
Subject: [PATCH] WIP

---
 include/cyclone/runtime.h |  1 +
 libs/cyclone/atomics.scm  | 37 ++++++++++++++++++++++++++++++++++++-
 runtime.c                 |  3 +++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/include/cyclone/runtime.h b/include/cyclone/runtime.h
index b9ae4ecd..f8185d18 100644
--- a/include/cyclone/runtime.h
+++ b/include/cyclone/runtime.h
@@ -453,6 +453,7 @@ object Cyc_is_integer(object o);
 #define Cyc_is_bytevector(o) (make_boolean(is_object_type(o) && ((list) o)->tag == bytevector_tag))
 #define Cyc_is_port(o)       (make_boolean(is_object_type(o) && ((list) o)->tag == port_tag))
 #define Cyc_is_mutex(o)      (make_boolean(is_object_type(o) && ((list) o)->tag == mutex_tag))
+#define Cyc_is_atomic(o)     (make_boolean(is_object_type(o) && ((list) o)->tag == atomic_tag))
 #define Cyc_is_cond_var(o)   (make_boolean(is_object_type(o) && ((list) o)->tag == cond_var_tag))
 #define Cyc_is_symbol(o)     (make_boolean(is_object_type(o) && ((list) o)->tag == symbol_tag))
 #define Cyc_is_string(o)     (make_boolean(is_object_type(o) && ((list) o)->tag == string_tag))
diff --git a/libs/cyclone/atomics.scm b/libs/cyclone/atomics.scm
index dae81541..be1445d4 100644
--- a/libs/cyclone/atomics.scm
+++ b/libs/cyclone/atomics.scm
@@ -12,4 +12,39 @@
 ;; probably want a (make-shared)
 ;; may also way a way to allocate multiple shared objects at once (since a minor GC will likely be req'd)
 
-;; (atomic? obj)
+;; (atom? obj)
+;; (atom obj)
+
+(define-c atom?
+  "(void *data, int argc, closure _, object k, object obj)"
+  " object result = Cyc_is_atomic(obj);
+    return_closcall1(data, k, result); ")
+;; 
+;; Alloc on the heap since by definition atoms are used by multiple threads
+;; 
+(define-c make-atom
+  "(void *data, int argc, closure _, object k, object obj)"
+  " int heap_grown;
+    atomic atm;
+    atomic_type tmp;
+    tmp.hdr.mark = gc_color_red;
+    tmp.hdr.grayed = 0;
+    tmp.tag = atomic_tag;
+    tmp.obj = obj;
+    atm = gc_alloc(((gc_thread_data *)data)->heap, sizeof(atomic_type), (char *)(&tmp), (gc_thread_data *)data, &heap_grown);
+    return_closcall1(data, k, atm); ")
+
+(define (atom . obj)
+  (if (pair? obj)
+      (make-atom (car obj))
+      (make-atom #f)))
+
+;; TODO:
+;; - ref atomic
+
+;; TODO:
+;; - swap, see https://clojure.github.io/clojure/clojure.core-api.html#clojure.core/swap!
+;; (swap! atom f)(swap! atom f x)(swap! atom f x y)(swap! atom f x y & args)
+
+;; TODO:
+;; - compare and swap?
diff --git a/runtime.c b/runtime.c
index 17a00614..2963d7a8 100644
--- a/runtime.c
+++ b/runtime.c
@@ -919,6 +919,9 @@ object Cyc_display(void *data, object x, FILE * port)
   case cond_var_tag:
     fprintf(port, "<condition variable %p>", x);
     break;
+  case atomic_tag:
+    fprintf(port, "<atom %p>", x);
+    break;
   case boolean_tag:
     fprintf(port, "#%s", ((boolean_type *) x)->desc);
     break;