1 files changed, 35 insertions, 0 deletions
diff --git a/src/runtime/sys_arm.go b/src/runtime/sys_arm.go
new file mode 100644
index 000000000..81777c710
--- /dev/null
+++ b/src/runtime/sys_arm.go
@@ -0,0 +1,35 @@
+// Copyright 2013 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"
+
+// adjust Gobuf as if it executed a call to fn with context ctxt
+// and then did an immediate Gosave.
+func gostartcall(buf *gobuf, fn, ctxt unsafe.Pointer) {
+	if buf.lr != 0 {
+		gothrow("invalid use of gostartcall")
+	}
+	buf.lr = buf.pc
+	buf.pc = uintptr(fn)
+	buf.ctxt = ctxt
+}
+
+// Called to rewind context saved during morestack back to beginning of function.
+// To help us, the linker emits a jmp back to the beginning right after the
+// call to morestack. We just have to decode and apply that jump.
+func rewindmorestack(buf *gobuf) {
+	var inst uint32
+	if buf.pc&3 == 0 && buf.pc != 0 {
+		inst = *(*uint32)(unsafe.Pointer(buf.pc))
+		if inst>>24 == 0x9a {
+			buf.pc += uintptr(int32(inst<<8)>>6) + 8
+			return
+		}
+	}
+
+	print("runtime: pc=", hex(buf.pc), " ", hex(inst), "\n")
+	gothrow("runtime: misuse of rewindmorestack")
+}