diff options
Diffstat (limited to 'src/runtime/atomic_386.go')
-rw-r--r-- | src/runtime/atomic_386.go | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/runtime/atomic_386.go b/src/runtime/atomic_386.go new file mode 100644 index 000000000..5563432ef --- /dev/null +++ b/src/runtime/atomic_386.go @@ -0,0 +1,91 @@ +// Copyright 2009 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 runtime + +import "unsafe" + +// The calls to nop are to keep these functions from being inlined. +// If they are inlined we have no guarantee that later rewrites of the +// code by optimizers will preserve the relative order of memory accesses. + +//go:nosplit +func atomicload(ptr *uint32) uint32 { + nop() + return *ptr +} + +//go:nosplit +func atomicloadp(ptr unsafe.Pointer) unsafe.Pointer { + nop() + return *(*unsafe.Pointer)(ptr) +} + +//go:nosplit +func xadd64(ptr *uint64, delta int64) uint64 { + for { + old := *ptr + if cas64(ptr, old, old+uint64(delta)) { + return old + uint64(delta) + } + } +} + +//go:nosplit +func xchg64(ptr *uint64, new uint64) uint64 { + for { + old := *ptr + if cas64(ptr, old, new) { + return old + } + } +} + +//go:noescape +func xadd(ptr *uint32, delta int32) uint32 + +//go:noescape +func xchg(ptr *uint32, new uint32) uint32 + +// xchgp cannot have a go:noescape annotation, because +// while ptr does not escape, new does. If new is marked as +// not escaping, the compiler will make incorrect escape analysis +// decisions about the value being xchg'ed. +// Instead, make xchgp a wrapper around the actual atomic. +// When calling the wrapper we mark ptr as noescape explicitly. + +//go:nosplit +func xchgp(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer { + return xchgp1(noescape(ptr), new) +} + +func xchgp1(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer + +//go:noescape +func xchguintptr(ptr *uintptr, new uintptr) uintptr + +//go:noescape +func atomicload64(ptr *uint64) uint64 + +//go:noescape +func atomicor8(ptr *uint8, val uint8) + +//go:noescape +func cas64(ptr *uint64, old, new uint64) bool + +//go:noescape +func atomicstore(ptr *uint32, val uint32) + +//go:noescape +func atomicstore64(ptr *uint64, val uint64) + +// atomicstorep cannot have a go:noescape annotation. +// See comment above for xchgp. + +//go:nosplit +func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) { + atomicstorep1(noescape(ptr), new) +} + +func atomicstorep1(ptr unsafe.Pointer, val unsafe.Pointer) |