*** empty log message ***

compiler_opt.h

@@ -0,0 +1,68 @@
+/*
+ * $Id$
+ * 
+ * Copyright (C) 2007 iptelorg GmbH
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/*
+ * compiler specific optimizations:
+ * --------------------------------
+ *
+ *   likely(expr)         - branch predicition optimization - is more likely
+ *                          that expr value will be 1 so optimize for this 
+ *                          case.
+ *                          Example: if (likely(p!=NULL)) {... }
+ *   unlikely(expr)       - branch prediction optimization - is unlikely that 
+ *                          expr will be true, so optimize for this case
+ *   prefetch(addr)        - will prefetch addr for reading
+ *   prefetch_w(addr)      - will prefetch add for writing
+ *   prefetch_loc_r(addr, loc) - prefetch for reading, data at addr has
+ *                                no temporal locality (loc==0), a short
+ *                                degree of temporal locality (loc==1), 
+ *                                moderate (loc==2) or high (loc==3).
+ *                                prefetch(addr) is equiv. to 
+ *                                prefetch_loc_r(addr, 3).
+ *  prefetch_loc_r(addr, loc) - like above but for writing.
+ */
+/* 
+ * History:
+ * --------
+ *  2007-05-14  created by andrei
+ */
+
+#ifndef __compiler_opt_h
+#define __compiler_opt_h
+
+#if __GNUC__ >= 3
+#define likely(expr)              __builtin_expect(!!(expr), 1)
+#define unlikely(expr)            __builtin_expect(!!(expr), 0)
+
+#define prefetch(addr)            __builtin_prefetch((addr))
+#define prefecth_w(addr)          __builtin_prefetch((addr), 1)
+#define prefetch_loc_r(addr, loc) __builtin_prefetch((addr), 0, (loc))
+#define prefetch_loc_w(addr, loc) __builtin_prefetch((addr), 1, (loc))
+
+#else /* __GNUC__ */
+
+#warning "No compiler optimizations supported try gcc 4.x"
+#define likely(expr) (expr)
+#define unlikely(expr) (expr)
+
+#define prefetch(addr)
+#define prefecth_w(addr)
+#define prefetch_loc_r(addr, loc)
+#define prefetch_loc_w(addr, loc)
+#endif /* __GNUC__ */
+
+#endif