1 // Copyright 2014 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 package runtime 6 7 import "unsafe" 8 9 // In addition to the 16 bits taken from the top, we can take 3 from the 10 // bottom, because node must be pointer-aligned, giving a total of 19 bits 11 // of count. 12 const ( 13 addrBits = 48 14 cntBits = 64 - addrBits + 3 15 ) 16 17 func lfstackPack(node *lfnode, cnt uintptr) uint64 { 18 return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1)) 19 } 20 21 func lfstackUnpack(val uint64) (node *lfnode, cnt uintptr) { 22 node = (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3))) 23 cnt = uintptr(val & (1<<cntBits - 1)) 24 return 25 } 26
