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// 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"
var locktab [57]struct {
l mutex
pad [_CacheLineSize - unsafe.Sizeof(mutex{})]byte
}
func addrLock(addr *uint64) *mutex {
return &locktab[(uintptr(unsafe.Pointer(addr))>>3)%uintptr(len(locktab))].l
}
// Atomic add and return new value.
//go:nosplit
func xadd(val *uint32, delta int32) uint32 {
for {
oval := *val
nval := oval + uint32(delta)
if cas(val, oval, nval) {
return nval
}
}
}
//go:nosplit
func xchg(addr *uint32, v uint32) uint32 {
for {
old := *addr
if cas(addr, old, v) {
return old
}
}
}
//go:nosplit
func xchgp(addr *unsafe.Pointer, v unsafe.Pointer) unsafe.Pointer {
for {
old := *addr
if casp(addr, old, v) {
return old
}
}
}
//go:nosplit
func xchguintptr(addr *uintptr, v uintptr) uintptr {
return uintptr(xchg((*uint32)(unsafe.Pointer(addr)), uint32(v)))
}
//go:nosplit
func atomicload(addr *uint32) uint32 {
return xadd(addr, 0)
}
//go:nosplit
func atomicloadp(addr unsafe.Pointer) unsafe.Pointer {
return unsafe.Pointer(uintptr(xadd((*uint32)(addr), 0)))
}
//go:nosplit
func atomicstorep(addr unsafe.Pointer, v unsafe.Pointer) {
for {
old := *(*unsafe.Pointer)(addr)
if casp((*unsafe.Pointer)(addr), old, v) {
return
}
}
}
//go:nosplit
func atomicstore(addr *uint32, v uint32) {
for {
old := *addr
if cas(addr, old, v) {
return
}
}
}
//go:nosplit
func cas64(addr *uint64, old, new uint64) bool {
var ok bool
systemstack(func() {
lock(addrLock(addr))
if *addr == old {
*addr = new
ok = true
}
unlock(addrLock(addr))
})
return ok
}
//go:nosplit
func xadd64(addr *uint64, delta int64) uint64 {
var r uint64
systemstack(func() {
lock(addrLock(addr))
r = *addr + uint64(delta)
*addr = r
unlock(addrLock(addr))
})
return r
}
//go:nosplit
func xchg64(addr *uint64, v uint64) uint64 {
var r uint64
systemstack(func() {
lock(addrLock(addr))
r = *addr
*addr = v
unlock(addrLock(addr))
})
return r
}
//go:nosplit
func atomicload64(addr *uint64) uint64 {
var r uint64
systemstack(func() {
lock(addrLock(addr))
r = *addr
unlock(addrLock(addr))
})
return r
}
//go:nosplit
func atomicstore64(addr *uint64, v uint64) {
systemstack(func() {
lock(addrLock(addr))
*addr = v
unlock(addrLock(addr))
})
}
//go:nosplit
func atomicor8(addr *uint8, v uint8) {
// Align down to 4 bytes and use 32-bit CAS.
uaddr := uintptr(unsafe.Pointer(addr))
addr32 := (*uint32)(unsafe.Pointer(uaddr &^ 3))
word := uint32(v) << ((uaddr & 3) * 8) // little endian
for {
old := *addr32
if cas(addr32, old, old|word) {
return
}
}
}
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