score: Add SMP barrier

1 files changed, 48 insertions, 0 deletions

diff --git a/cpukit/score/src/smpbarrierwait.c b/cpukit/score/src/smpbarrierwait.c
new file mode 100644
index 0000000000..0a3cedba00
--- /dev/null
+++ b/cpukit/score/src/smpbarrierwait.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2013-2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/score/smpbarrier.h>
+
+void _SMP_barrier_Wait(
+  SMP_barrier_Control *control,
+  SMP_barrier_State *state,
+  unsigned int count
+)
+{
+  unsigned int sense = ~state->sense;
+  unsigned int previous_value;
+
+  state->sense = sense;
+
+  previous_value = _Atomic_Fetch_add_uint(
+    &control->value,
+    1U,
+    ATOMIC_ORDER_RELAXED
+  );
+
+  if ( previous_value + 1U == count ) {
+    _Atomic_Store_uint( &control->value, 0U, ATOMIC_ORDER_RELAXED );
+    _Atomic_Store_uint( &control->sense, sense, ATOMIC_ORDER_RELEASE );
+  } else {
+    while (
+      _Atomic_Load_uint( &control->sense, ATOMIC_ORDER_ACQUIRE ) != sense
+    ) {
+      /* Wait */
+    }
+  }
+}