DR4
	DR5
	DR6
	DR7
	DR8
	DR9
	DR10
	DR11
	DR12
	DR13
	DR14
	DR15

	// Task registers.
	TR0
	TR1
	TR2
	TR3
	TR4
	TR5
	TR6
	TR7
)

const regMax = TR7

func (Reg) isArg() {}

func (r Reg) String() string {
	i := int(r)
	if i < 0 || i >= len(regNames) || regNames[i] == "" {
		return fmt.Sprintf("Reg(%d)", i)
	}
	return regNames[i]

	DR3:  "%db3",
	DR4:  "%db4",
	DR5:  "%db5",
	DR6:  "%db6",
	DR7:  "%db7",
	TR0:  "%tr0",
	TR1:  "%tr1",
	TR2:  "%tr2",
	TR3:  "%tr3",
	TR4:  "%tr4",
	TR5:  "%tr5",
	TR6:  "%tr6",
	TR7:  "%tr7",
}

var gnuOp = map[Op]string{
	CBW:       "cbtw",
	CDQ:       "cltd",
	CMPSD:     "cmpsl",
	CMPSD_XMM: "cmpsd",
	CWD:       "cwtd",
	CWDE:      "cwtl",
	CQO:       "cqto",