pcdata.To.Type = TYPE_CONST
	pcdata.To.Offset = -1

	return pcdata
}

// StartUnsafePoint generates PCDATA Progs after p to mark the
// beginning of an unsafe point. The unsafe point starts immediately
// after p.
// It returns the last Prog generated.
func (ctxt *Link) StartUnsafePoint(p *Prog, newprog ProgAlloc) *Prog {
	pcdata := Appendp(p, newprog)
	pcdata.As = APCDATA

				// code will not see a half-updated stack frame.
				// This sequence is not async preemptible, as if we open a frame
				// at the current SP, it will clobber the saved LR.
				q = c.ctxt.StartUnsafePoint(p, c.newprog)

				q = obj.Appendp(q, c.newprog)
				q.As = AMOVD
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REG_LR
				q.To.Type = obj.TYPE_MEM
				q.To.Reg = REGSP

				// code will not see a half-updated stack frame.
				// This sequence is not async preemptible, as if we open a frame
				// at the current SP, it will clobber the saved LR.
				q = c.ctxt.StartUnsafePoint(q, c.newprog)

				q = obj.Appendp(q, newprog)
				q.As = mov
				q.Pos = p.Pos
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REGLINK
				q.To.Type = obj.TYPE_MEM
				q.To.Offset = int64(-autosize)

	// If we get preempted here, when resumed the preemption request is
	// cleared, but we'll still call morestack, which will double the stack
	// unnecessarily. See issue #35470.
	p = c.ctxt.StartUnsafePoint(p, c.newprog)

	q := (*obj.Prog)(nil)
	if framesize <= abi.StackSmall {
		// small stack: SP < stackguard
		//	CMP	stackguard, SP

		p = obj.Appendp(p, c.newprog)
		p.As = ACMP

		// If we get preempted here, when resumed the preemption request is
		// cleared, but we'll still call morestack, which will double the stack
		// unnecessarily. See issue #35470.
		p = ctxt.StartUnsafePoint(p, newprog)
	} else if framesize <= abi.StackBig {
		// large stack: SP-framesize <= stackguard-StackSmall
		//	LEAQ -xxx(SP), tmp
		//	CMPQ tmp, stackguard
		p = obj.Appendp(p, newprog)

	// If we get preempted here, when resumed the preemption request is
	// cleared, but we'll still call morestack, which will double the stack
	// unnecessarily. See issue #35470.
	p = c.ctxt.StartUnsafePoint(p, c.newprog)

	if framesize <= abi.StackSmall {
		// small stack: SP < stackguard
		//	CMP	stackguard, SP
		p = obj.Appendp(p, c.newprog)

		p.As = ACMP
		p.From.Type = obj.TYPE_REG

				// code will not see a half-updated stack frame.
				// This sequence is not async preemptible, as if we open a frame
				// at the current SP, it will clobber the saved LR.
				q = c.ctxt.StartUnsafePoint(q, c.newprog)

				q = obj.Appendp(q, newprog)
				q.As = mov
				q.Pos = p.Pos
				q.From.Type = obj.TYPE_REG
				q.From.Reg = REGLINK
				q.To.Type = obj.TYPE_MEM
				q.To.Offset = int64(-autosize)

					q.From.Type = obj.TYPE_REG
					q.From.Reg = REG_LR
					q.To.Type = obj.TYPE_REG
					q.To.Reg = REG_R29 // REGTMP may be used to synthesize large offset in the next instruction

					q = c.ctxt.StartUnsafePoint(q, c.newprog)

					q = obj.Appendp(q, c.newprog)
					q.As = AMOVD
					q.Pos = p.Pos
					q.From.Type = obj.TYPE_REG
					q.From.Reg = REG_R29
					q.To.Type = obj.TYPE_MEM

	prologue := text

	if !cursym.Func().Text.From.Sym.NoSplit() {
		prologue = stacksplit(ctxt, prologue, cursym, newprog, stacksize) // emit split check
	}

	if stacksize != 0 {
		prologue = ctxt.StartUnsafePoint(prologue, newprog)

		// Actually save LR.
		prologue = obj.Appendp(prologue, newprog)
		prologue.As = AMOV
		prologue.From = obj.Addr{Type: obj.TYPE_REG, Reg: REG_LR}