// require special handling.
func IsLoong64RDTIME(op obj.As) bool {
	switch op {
	case loong64.ARDTIMELW, loong64.ARDTIMEHW, loong64.ARDTIMED:
		return true
	}
	return false
}

func IsLoong64AMO(op obj.As) bool {
	return loong64.IsAtomicInst(op)
}

func loong64RegisterNumber(name string, n int16) (int16, bool) {
	switch name {
	case "F":
		if 0 <= n && n <= 31 {
			return loong64.REG_F0 + n, true

			prog.From = a[0]
			prog.Reg = p.getRegister(prog, op, &a[1])
			prog.To = a[2]
		case sys.Loong64:
			switch {
			// Loong64 atomic instructions with one input and two outputs.
			case arch.IsLoong64AMO(op):
				prog.From = a[0]
				prog.To = a[1]
				prog.RegTo2 = a[2].Reg
			default:
				prog.From = a[0]
				prog.Reg = p.getRegister(prog, op, &a[1])
				prog.To = a[2]
			}
		case sys.ARM: