1 files changed, 111 insertions, 0 deletions
diff --git a/cas.h b/cas.h
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--- /dev/null
+++ b/cas.h
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+/*
+ * File     : cas.h
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 25/01/13
+ * License  :
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining
+ *  a copy of this software and associated documentation files (the
+ *  "Software"), to deal in the Software without restriction, including
+ *  without limitation the rights to use, copy, modify, merge, publish,
+ *  distribute, sublicense, and/or sell copies of the Software, and to
+ *  permit persons to whom the Software is furnished to do so, subject to
+ *  the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be
+ *  included in all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#ifndef _CAS_H_
+#define _CAS_H_
+
+# ifdef __cplusplus
+extern "C" {
+# endif /* __cplusplus */
+
+#include <stdint.h>
+
+#if defined(__i386__) && defined(__GNUC__)
+
+struct _cas_pointer_t
+{
+    uint32_t lo;
+    uint32_t hi;
+} __attribute__ (( __aligned__( 8 ) ));
+
+#define _hi(p,v)    ((p).hi=(uint32_t)(v))
+#define _lo(p,v)    ((p).lo=(uint32_t)(v))
+#define _hi_eq(p,v) ((p).hi==(uint32_t)(v))
+#define _lo_eq(p,v) ((p).lo==(uint32_t)(v))
+
+#elif defined(__x86_64__) && defined(__GNUC__)
+
+struct _cas_pointer_t
+{
+    uint64_t lo;
+    uint64_t hi;
+} __attribute__ (( __aligned__( 16 ) ));
+
+#define _hi(p,v)    ((p).hi=(uint64_t)(v))
+#define _lo(p,v)    ((p).lo=(uint64_t)(v))
+#define _hi_eq(p,v) ((p).hi==(uint64_t)(v))
+#define _lo_eq(p,v) ((p).lo==(uint64_t)(v))
+
+#else
+#error "cas not implemented yet for your arch"
+#endif
+
+typedef struct _cas_pointer_t cas_pointer_t;
+
+inline int cas(volatile cas_pointer_t* mem, cas_pointer_t old_val, cas_pointer_t new_val)
+{
+    char success;
+
+#if defined(__i386__) && defined(__GNUC__)
+
+    asm volatile("lock; cmpxchg8b (%6);"
+            "setz %7; "
+            : "=a" ( old_val.lo ),
+              "=d" ( old_val.hi )
+            : "0"  ( old_val.lo ),
+              "1"  ( old_val.hi ),
+              "b"  ( new_val.lo ),
+              "c"  ( new_val.hi ),
+              "r"  ( mem ),
+              "m"  ( success )
+            : "cc", "memory"
+            );
+
+#elif defined(__x86_64__) && defined(__GNUC__)
+
+    asm volatile (
+            "lock cmpxchg16b %1\n\t"
+            "setz %0"
+            : "=q" ( success )
+            , "+m" ( *mem )
+            , "+d" ( old_val.hi )
+            , "+a" ( old_val.lo )
+            : "c"  ( new_val.hi )
+            , "b"  ( new_val.lo )
+            : "cc"
+            );
+#endif
+
+    return (int)success;
+}
+
+# ifdef __cplusplus
+}
+# endif /* __cplusplus */
+
+# endif /* _CAS_H_ */
+