[dpdk-dev] [PATCH v3 1/2] eal: add 128-bit cmpset (x86-64 only)

[Gage Eads <gage.eads@intel.com>]

This operation can be used for non-blocking algorithms, such as a
non-blocking stack or ring.

Signed-off-by: Gage Eads <gage.eads@intel.com>
---
 .../common/include/arch/x86/rte_atomic_64.h        | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
index fd2ec9c53..34c2addf8 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
@@ -34,6 +34,7 @@
 /*
  * Inspired from FreeBSD src/sys/amd64/include/atomic.h
  * Copyright (c) 1998 Doug Rabson
+ * Copyright (c) 2019 Intel Corporation
  * All rights reserved.
  */
 
@@ -208,4 +209,25 @@ static inline void rte_atomic64_clear(rte_atomic64_t *v)
 }
 #endif
 
+static inline int
+rte_atomic128_cmpset(volatile uint64_t *dst, uint64_t *exp, uint64_t *src)
+{
+	uint8_t res;
+
+	asm volatile (
+		      MPLOCKED
+		      "cmpxchg16b %[dst];"
+		      " sete %[res]"
+		      : [dst] "=m" (*dst),
+			[res] "=r" (res)
+		      : "c" (src[1]),
+			"b" (src[0]),
+			"m" (*dst),
+			"d" (exp[1]),
+			"a" (exp[0])
+		      : "memory");
+
+	return res;
+}
+
 #endif /* _RTE_ATOMIC_X86_64_H_ */
-- 
2.13.6