runtime: merge 64bit lfstack impls

Merge all the 64bit lfstack impls into one file, adjust build tags to
match.

Merge all the comments on the various lfstack implementations for
posterity.

lfstack_amd64.go can probably be merged, but it is slightly different so
that will happen in a followup.

Change-Id: I5362d5e127daa81c9cb9d4fa8a0cc5c5e5c2707c
Reviewed-on: https://go-review.googlesource.com/21591
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>

1 files changed, 0 insertions, 25 deletions

diff --git a/src/runtime/lfstack_darwin_arm64.go b/src/runtime/lfstack_darwin_arm64.go
deleted file mode 100644
index f48d76382b..0000000000
--- a/src/runtime/lfstack_darwin_arm64.go
+++ /dev/null
@@ -1,25 +0,0 @@
-// 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
-}