From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Date: Wed, 13 May 2009 15:15:37 +0000 (-0400)
Subject: Rewrite of likely, unlikely, barrier and ACCESS_ONCE
X-Git-Tag: v0.1~231
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=2dc5fa0f7cfbfb0a64a7a67b39626650e863f16a;p=urcu.git

Rewrite of likely, unlikely, barrier and ACCESS_ONCE

compiler.h now licensed under MIT-style license.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---

diff --git a/LICENSE b/LICENSE
index fa10831..f02264e 100644
--- a/LICENSE
+++ b/LICENSE
@@ -38,6 +38,7 @@ This license applies to :
 
 arch_atomic_x86.h
 arch_atomic_ppc.h
+compiler.h
 
 
 * GPLv2
diff --git a/compiler.h b/compiler.h
index fb09ca2..717465c 100644
--- a/compiler.h
+++ b/compiler.h
@@ -25,6 +25,11 @@
  * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  */
 
+#define likely()	__builtin_expect(!!(x), 1)
+#define unlikely()	__builtin_expect(!!(x), 0)
+
+#define	barrier()	asm volatile("" : : : "memory");
+
 /*
  * Instruct the compiler to perform only a single access to a variable
  * (prohibits merging and refetching). The compiler is also forbidden to reorder
@@ -37,5 +42,6 @@
  * use is to mediate communication between process-level code and irq/NMI
  * handlers, all running on the same CPU.
  */
+#define ACCESS_ONCE(x)	(*(volatile typeof(x) *)&x)
 
 #endif /* _COMPILER_H */