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// Copyright 2012 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.
// Lock-free stack.
// The following code runs only on g0 stack.
package runtime
import "unsafe"
func lfstackpush(head *uint64, node *lfnode) {
node.pushcnt++
new := lfstackPack(node, node.pushcnt)
if node1, _ := lfstackUnpack(new); node1 != node {
println("runtime: lfstackpush invalid packing: node=", node, " cnt=", hex(node.pushcnt), " packed=", hex(new), " -> node=", node1, "\n")
gothrow("lfstackpush")
}
for {
old := atomicload64(head)
node.next, _ = lfstackUnpack(old)
if cas64(head, old, new) {
break
}
}
}
func lfstackpop(head *uint64) unsafe.Pointer {
for {
old := atomicload64(head)
if old == 0 {
return nil
}
node, _ := lfstackUnpack(old)
node2 := (*lfnode)(atomicloadp(unsafe.Pointer(&node.next)))
new := uint64(0)
if node2 != nil {
new = lfstackPack(node2, node2.pushcnt)
}
if cas64(head, old, new) {
return unsafe.Pointer(node)
}
}
}
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