github.com/zebozhuang/go@v0.0.0-20200207033046-f8a98f6f5c5d/src/runtime/internal/atomic/atomic_mipsx.go (about)

     1  // Copyright 2016 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 mips mipsle
     6  
     7  package atomic
     8  
     9  import (
    10  	"runtime/internal/sys"
    11  	"unsafe"
    12  )
    13  
    14  // TODO implement lock striping
    15  var lock struct {
    16  	state uint32
    17  	pad   [sys.CacheLineSize - 4]byte
    18  }
    19  
    20  //go:noescape
    21  func spinLock(state *uint32)
    22  
    23  //go:noescape
    24  func spinUnlock(state *uint32)
    25  
    26  //go:nosplit
    27  func lockAndCheck(addr *uint64) {
    28  	// ensure 8-byte alignement
    29  	if uintptr(unsafe.Pointer(addr))&7 != 0 {
    30  		addr = nil
    31  	}
    32  	// force dereference before taking lock
    33  	_ = *addr
    34  
    35  	spinLock(&lock.state)
    36  }
    37  
    38  //go:nosplit
    39  func unlock() {
    40  	spinUnlock(&lock.state)
    41  }
    42  
    43  //go:nosplit
    44  func unlockNoFence() {
    45  	lock.state = 0
    46  }
    47  
    48  //go:nosplit
    49  func Xadd64(addr *uint64, delta int64) (new uint64) {
    50  	lockAndCheck(addr)
    51  
    52  	new = *addr + uint64(delta)
    53  	*addr = new
    54  
    55  	unlock()
    56  	return
    57  }
    58  
    59  //go:nosplit
    60  func Xchg64(addr *uint64, new uint64) (old uint64) {
    61  	lockAndCheck(addr)
    62  
    63  	old = *addr
    64  	*addr = new
    65  
    66  	unlock()
    67  	return
    68  }
    69  
    70  //go:nosplit
    71  func Cas64(addr *uint64, old, new uint64) (swapped bool) {
    72  	lockAndCheck(addr)
    73  
    74  	if (*addr) == old {
    75  		*addr = new
    76  		unlock()
    77  		return true
    78  	}
    79  
    80  	unlockNoFence()
    81  	return false
    82  }
    83  
    84  //go:nosplit
    85  func Load64(addr *uint64) (val uint64) {
    86  	lockAndCheck(addr)
    87  
    88  	val = *addr
    89  
    90  	unlock()
    91  	return
    92  }
    93  
    94  //go:nosplit
    95  func Store64(addr *uint64, val uint64) {
    96  	lockAndCheck(addr)
    97  
    98  	*addr = val
    99  
   100  	unlock()
   101  	return
   102  }
   103  
   104  //go:noescape
   105  func Xadd(ptr *uint32, delta int32) uint32
   106  
   107  //go:noescape
   108  func Xadduintptr(ptr *uintptr, delta uintptr) uintptr
   109  
   110  //go:noescape
   111  func Xchg(ptr *uint32, new uint32) uint32
   112  
   113  //go:noescape
   114  func Xchguintptr(ptr *uintptr, new uintptr) uintptr
   115  
   116  //go:noescape
   117  func Load(ptr *uint32) uint32
   118  
   119  //go:noescape
   120  func Loadp(ptr unsafe.Pointer) unsafe.Pointer
   121  
   122  //go:noescape
   123  func And8(ptr *uint8, val uint8)
   124  
   125  //go:noescape
   126  func Or8(ptr *uint8, val uint8)
   127  
   128  //go:noescape
   129  func Store(ptr *uint32, val uint32)
   130  
   131  // NO go:noescape annotation; see atomic_pointer.go.
   132  func StorepNoWB(ptr unsafe.Pointer, val unsafe.Pointer)