mirror of
https://github.com/golang/go
synced 2024-10-03 03:01:21 -06:00
846ee0465b
Change-Id: Ibda6a5bedaff57fd161d63fc04ad260931d34413 Reviewed-on: https://go-review.googlesource.com/7142 Reviewed-by: Russ Cox <rsc@golang.org>
26 lines
732 B
Go
26 lines
732 B
Go
// Copyright 2014 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"
|
|
|
|
// In addition to the 16 bits taken from the top, we can take 3 from the
|
|
// bottom, because node must be pointer-aligned, giving a total of 19 bits
|
|
// of count.
|
|
const (
|
|
addrBits = 48
|
|
cntBits = 64 - addrBits + 3
|
|
)
|
|
|
|
func lfstackPack(node *lfnode, cnt uintptr) uint64 {
|
|
return uint64(uintptr(unsafe.Pointer(node)))<<(64-addrBits) | uint64(cnt&(1<<cntBits-1))
|
|
}
|
|
|
|
func lfstackUnpack(val uint64) (node *lfnode, cnt uintptr) {
|
|
node = (*lfnode)(unsafe.Pointer(uintptr(val >> cntBits << 3)))
|
|
cnt = uintptr(val & (1<<cntBits - 1))
|
|
return
|
|
}
|