Imported Upstream version 60upstream/60

1 files changed, 68 insertions, 0 deletions

diff --git a/src/pkg/sync/atomic/doc.go b/src/pkg/sync/atomic/doc.go
new file mode 100644
index 000000000..b35eb539c
--- /dev/null
+++ b/src/pkg/sync/atomic/doc.go
@@ -0,0 +1,68 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package atomic provides low-level atomic memory primitives
+// useful for implementing synchronization algorithms.
+//
+// These functions require great care to be used correctly.
+// Except for special, low-level applications, synchronization is better
+// done with channels or the facilities of the sync package.
+// Share memory by communicating;
+// don't communicate by sharing memory.
+//
+// The compare-and-swap operation, implemented by the CompareAndSwapT
+// functions, is the atomic equivalent of:
+//
+//	if *val == old {
+//		*val = new
+//		return true
+//	}
+//	return false
+//
+package atomic
+
+// BUG(rsc): On ARM, the 64-bit functions use instructions unavailable before ARM 11.
+//
+// On x86-32, the 64-bit functions use instructions unavailable before the Pentium.
+
+// CompareAndSwapInt32 executes the compare-and-swap operation for an int32 value.
+func CompareAndSwapInt32(val *int32, old, new int32) (swapped bool)
+
+// CompareAndSwapInt64 executes the compare-and-swap operation for an int64 value.
+func CompareAndSwapInt64(val *int64, old, new int64) (swapped bool)
+
+// CompareAndSwapUint32 executes the compare-and-swap operation for a uint32 value.
+func CompareAndSwapUint32(val *uint32, old, new uint32) (swapped bool)
+
+// CompareAndSwapUint64 executes the compare-and-swap operation for a uint64 value.
+func CompareAndSwapUint64(val *uint64, old, new uint64) (swapped bool)
+
+// CompareAndSwapUintptr executes the compare-and-swap operation for a uintptr value.
+func CompareAndSwapUintptr(val *uintptr, old, new uintptr) (swapped bool)
+
+// AddInt32 atomically adds delta to *val and returns the new value.
+func AddInt32(val *int32, delta int32) (new int32)
+
+// AddUint32 atomically adds delta to *val and returns the new value.
+func AddUint32(val *uint32, delta uint32) (new uint32)
+
+// AddInt64 atomically adds delta to *val and returns the new value.
+func AddInt64(val *int64, delta int64) (new int64)
+
+// AddUint64 atomically adds delta to *val and returns the new value.
+func AddUint64(val *uint64, delta uint64) (new uint64)
+
+// AddUintptr atomically adds delta to *val and returns the new value.
+func AddUintptr(val *uintptr, delta uintptr) (new uintptr)
+
+// LoadInt32 atomically loads *addr.
+func LoadInt32(addr *int32) (val int32)
+
+// LoadUint32 atomically loads *addr.
+func LoadUint32(addr *uint32) (val uint32)
+
+// Helper for ARM.  Linker will discard on other systems
+func panic64() {
+	panic("sync/atomic: broken 64-bit atomic operations (buggy QEMU)")
+}