runtime: added go files for linux/mips64{,le} support

Change-Id: I14b537922b97d4bce9e0523d98a822da906348f1
Reviewed-on: https://go-review.googlesource.com/14447
Reviewed-by: Minux Ma <minux@golang.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/src/runtime/lfstack_linux_mips64x.go b/src/runtime/lfstack_linux_mips64x.go
new file mode 100644
index 0000000000..49b65585f4
--- /dev/null
+++ b/src/runtime/lfstack_linux_mips64x.go
@@ -0,0 +1,32 @@
+// Copyright 2015 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.
+
+// +build mips64 mips64le
+// +build linux
+
+package runtime
+
+import "unsafe"
+
+// On mips64, Linux limits the user address space to 40 bits (see
+// TASK_SIZE64 in the Linux kernel).  This has grown over time,
+// so here we allow 48 bit addresses.
+//
+// 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
+}