runtime: break out system-specific constants into package sys
runtime/internal/sys will hold system-, architecture- and config-
specific constants.
Updates #11647
Change-Id: I6db29c312556087a42e8d2bdd9af40d157c56b54
Reviewed-on: https://go-review.googlesource.com/16817
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/src/runtime/internal/sys/stubs.go b/src/runtime/internal/sys/stubs.go
new file mode 100644
index 0000000..0a94502
--- /dev/null
+++ b/src/runtime/internal/sys/stubs.go
@@ -0,0 +1,11 @@
+// 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 sys
+
+// Declarations for runtime services implemented in C or assembly.
+
+const PtrSize = 4 << (^uintptr(0) >> 63) // unsafe.Sizeof(uintptr(0)) but an ideal const
+const RegSize = 4 << (^Uintreg(0) >> 63) // unsafe.Sizeof(uintreg(0)) but an ideal const
+const SpAlign = 1*(1-GoarchArm64) + 16*GoarchArm64 // SP alignment: 1 normally, 16 for ARM64
