diff options
Diffstat (limited to 'src/pkg/sync/atomic/doc.go')
| -rw-r--r-- | src/pkg/sync/atomic/doc.go | 55 |
1 files changed, 35 insertions, 20 deletions
diff --git a/src/pkg/sync/atomic/doc.go b/src/pkg/sync/atomic/doc.go index ecb4808ce..27a12c984 100644 --- a/src/pkg/sync/atomic/doc.go +++ b/src/pkg/sync/atomic/doc.go @@ -2,6 +2,8 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. +// +build !race + // Package atomic provides low-level atomic memory primitives // useful for implementing synchronization algorithms. // @@ -14,54 +16,67 @@ // The compare-and-swap operation, implemented by the CompareAndSwapT // functions, is the atomic equivalent of: // -// if *val == old { -// *val = new +// if *addr == old { +// *addr = new // return true // } // return false // +// The add operation, implemented by the AddT functions, is the atomic +// equivalent of: +// +// *addr += delta +// return *addr +// +// The load and store operations, implemented by the LoadT and StoreT +// functions, are the atomic equivalents of "return *addr" and +// "*addr = val". +// package atomic import ( "unsafe" ) -// BUG(rsc): On ARM, the 64-bit functions use instructions unavailable before ARM 11. +// BUG(rsc): On x86-32, the 64-bit functions use instructions unavailable before the Pentium MMX. // -// On x86-32, the 64-bit functions use instructions unavailable before the Pentium MMX. +// On both ARM and x86-32, it is the caller's responsibility to arrange for 64-bit +// alignment of 64-bit words accessed atomically. The first word in a global +// variable or in an allocated struct or slice can be relied upon to be +// 64-bit aligned. // CompareAndSwapInt32 executes the compare-and-swap operation for an int32 value. -func CompareAndSwapInt32(val *int32, old, new int32) (swapped bool) +func CompareAndSwapInt32(addr *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) +func CompareAndSwapInt64(addr *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) +func CompareAndSwapUint32(addr *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) +func CompareAndSwapUint64(addr *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) +func CompareAndSwapUintptr(addr *uintptr, old, new uintptr) (swapped bool) // CompareAndSwapPointer executes the compare-and-swap operation for a unsafe.Pointer value. -func CompareAndSwapPointer(val *unsafe.Pointer, old, new unsafe.Pointer) (swapped bool) +func CompareAndSwapPointer(addr *unsafe.Pointer, old, new unsafe.Pointer) (swapped bool) -// AddInt32 atomically adds delta to *val and returns the new value. -func AddInt32(val *int32, delta int32) (new int32) +// AddInt32 atomically adds delta to *addr and returns the new value. +func AddInt32(addr *int32, delta int32) (new int32) -// AddUint32 atomically adds delta to *val and returns the new value. -func AddUint32(val *uint32, delta uint32) (new uint32) +// AddUint32 atomically adds delta to *addr and returns the new value. +func AddUint32(addr *uint32, delta uint32) (new uint32) -// AddInt64 atomically adds delta to *val and returns the new value. -func AddInt64(val *int64, delta int64) (new int64) +// AddInt64 atomically adds delta to *addr and returns the new value. +func AddInt64(addr *int64, delta int64) (new int64) -// AddUint64 atomically adds delta to *val and returns the new value. -func AddUint64(val *uint64, delta uint64) (new uint64) +// AddUint64 atomically adds delta to *addr and returns the new value. +func AddUint64(addr *uint64, delta uint64) (new uint64) -// AddUintptr atomically adds delta to *val and returns the new value. -func AddUintptr(val *uintptr, delta uintptr) (new uintptr) +// AddUintptr atomically adds delta to *addr and returns the new value. +func AddUintptr(addr *uintptr, delta uintptr) (new uintptr) // LoadInt32 atomically loads *addr. func LoadInt32(addr *int32) (val int32) |