mirror of
https://github.com/golang/go
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5fce15a2a3
While we are here, add the linux/power64 version. LGTM=austin R=austin CC=aram, dvyukov, golang-codereviews https://golang.org/cl/177750043
25 lines
843 B
Go
25 lines
843 B
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import "unsafe"
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// On AMD64, virtual addresses are 48-bit numbers sign extended to 64.
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// We shift the address left 16 to eliminate the sign extended part and make
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// room in the bottom for the count.
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// In addition to the 16 bits taken from the top, we can take 3 from the
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// bottom, because node must be pointer-aligned, giving a total of 19 bits
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// of count.
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func lfstackPack(node *lfnode, cnt uintptr) uint64 {
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return uint64(uintptr(unsafe.Pointer(node)))<<16 | uint64(cnt&(1<<19-1))
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}
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func lfstackUnpack(val uint64) (node *lfnode, cnt uintptr) {
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node = (*lfnode)(unsafe.Pointer(uintptr(int64(val) >> 19 << 3)))
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cnt = uintptr(val & (1<<19 - 1))
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return
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}
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