github.com/hbdrawn/golang@v0.0.0-20141214014649-6b835209aba2/src/runtime/atomic_amd64x.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build amd64 amd64p32
     6  
     7  package runtime
     8  
     9  import "unsafe"
    10  
    11  // The calls to nop are to keep these functions from being inlined.
    12  // If they are inlined we have no guarantee that later rewrites of the
    13  // code by optimizers will preserve the relative order of memory accesses.
    14  
    15  //go:nosplit
    16  func atomicload(ptr *uint32) uint32 {
    17  	nop()
    18  	return *ptr
    19  }
    20  
    21  //go:nosplit
    22  func atomicloadp(ptr unsafe.Pointer) unsafe.Pointer {
    23  	nop()
    24  	return *(*unsafe.Pointer)(ptr)
    25  }
    26  
    27  //go:nosplit
    28  func atomicload64(ptr *uint64) uint64 {
    29  	nop()
    30  	return *ptr
    31  }
    32  
    33  //go:noescape
    34  func xadd(ptr *uint32, delta int32) uint32
    35  
    36  //go:noescape
    37  func xadd64(ptr *uint64, delta int64) uint64
    38  
    39  //go:noescape
    40  func xchg(ptr *uint32, new uint32) uint32
    41  
    42  //go:noescape
    43  func xchg64(ptr *uint64, new uint64) uint64
    44  
    45  // xchgp cannot have a go:noescape annotation, because
    46  // while ptr does not escape, new does. If new is marked as
    47  // not escaping, the compiler will make incorrect escape analysis
    48  // decisions about the value being xchg'ed.
    49  // Instead, make xchgp a wrapper around the actual atomic.
    50  // When calling the wrapper we mark ptr as noescape explicitly.
    51  
    52  //go:nosplit
    53  func xchgp(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer {
    54  	return xchgp1(noescape(ptr), new)
    55  }
    56  
    57  func xchgp1(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer
    58  
    59  //go:noescape
    60  func xchguintptr(ptr *uintptr, new uintptr) uintptr
    61  
    62  //go:noescape
    63  func atomicor8(ptr *uint8, val uint8)
    64  
    65  //go:noescape
    66  func cas64(ptr *uint64, old, new uint64) bool
    67  
    68  //go:noescape
    69  func atomicstore(ptr *uint32, val uint32)
    70  
    71  //go:noescape
    72  func atomicstore64(ptr *uint64, val uint64)
    73  
    74  // atomicstorep cannot have a go:noescape annotation.
    75  // See comment above for xchgp.
    76  
    77  //go:nosplit
    78  func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) {
    79  	atomicstorep1(noescape(ptr), new)
    80  }
    81  
    82  func atomicstorep1(ptr unsafe.Pointer, val unsafe.Pointer)