func (p *Parser) branch(addr *obj.Addr, target *obj.Prog) {
	*addr = obj.Addr{
		Type:  obj.TYPE_BRANCH,
		Index: 0,
	}
	addr.Val = target
}

// asmInstruction assembles an instruction.
// MOVW R9, (R10)
func (p *Parser) asmInstruction(op obj.As, cond string, a []obj.Addr) {
	// fmt.Printf("%s %+v\n", op, a)
	prog := &obj.Prog{
		Ctxt: p.ctxt,
		Pos:  p.pos(),
		As:   op,
	}
	switch len(a) {