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PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 59 insertions, 0 deletions

diff --git a/pkg/atomicbitops/atomic_bitops.go b/pkg/atomicbitops/atomic_bitops.go
new file mode 100644
index 000000000..6635ea0d2
--- /dev/null
+++ b/pkg/atomicbitops/atomic_bitops.go
@@ -0,0 +1,59 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build amd64
+
+// Package atomicbitops provides basic bitwise operations in an atomic way.
+// The implementation on amd64 leverages the LOCK prefix directly instead of
+// relying on the generic cas primitives.
+//
+// WARNING: the bitwise ops provided in this package doesn't imply any memory
+// ordering. Using them to construct locks must employ proper memory barriers.
+package atomicbitops
+
+// AndUint32 atomically applies bitwise and operation to *addr with val.
+func AndUint32(addr *uint32, val uint32)
+
+// OrUint32 atomically applies bitwise or operation to *addr with val.
+func OrUint32(addr *uint32, val uint32)
+
+// XorUint32 atomically applies bitwise xor operation to *addr with val.
+func XorUint32(addr *uint32, val uint32)
+
+// CompareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns
+// the value previously stored at addr.
+func CompareAndSwapUint32(addr *uint32, old, new uint32) uint32
+
+// AndUint64 atomically applies bitwise and operation to *addr with val.
+func AndUint64(addr *uint64, val uint64)
+
+// OrUint64 atomically applies bitwise or operation to *addr with val.
+func OrUint64(addr *uint64, val uint64)
+
+// XorUint64 atomically applies bitwise xor operation to *addr with val.
+func XorUint64(addr *uint64, val uint64)
+
+// CompareAndSwapUint64 is like sync/atomic.CompareAndSwapUint64, but returns
+// the value previously stored at addr.
+func CompareAndSwapUint64(addr *uint64, old, new uint64) uint64
+
+// IncUnlessZeroInt32 increments the value stored at the given address and
+// returns true; unless the value stored in the pointer is zero, in which case
+// it is left unmodified and false is returned.
+func IncUnlessZeroInt32(addr *int32) bool
+
+// DecUnlessOneInt32 decrements the value stored at the given address and
+// returns true; unless the value stored in the pointer is 1, in which case it
+// is left unmodified and false is returned.
+func DecUnlessOneInt32(addr *int32) bool