if immhalf(int32(c.instoffset)) { /* n.b. that it will also satisfy immrot */
					if immfloat(t) {
						return C_HFOREG
					}
					return C_HOREG
				}

				if immfloat(t) {
					return C_FOREG /* n.b. that it will also satisfy immrot */
				}
				if immrot(uint32(c.instoffset)) != 0 {
					return C_SROREG
				}
				if immhalf(int32(c.instoffset)) {
					return C_HOREG

	return fmt.Sprintf("#%#x", uint32(i))
}

// An ImmAlt is an alternate encoding of an integer constant.
type ImmAlt struct {
	Val uint8
	Rot uint8
}

func (ImmAlt) IsArg() {}

func (i ImmAlt) Imm() Imm {
	v := uint32(i.Val)
	r := uint(i.Rot)
	return Imm(v>>r | v<<(32-r))
}

func (i ImmAlt) String() string {
	return fmt.Sprintf("#%#x, %d", i.Val, i.Rot)
}

	case Imm:
		switch inst.Op &^ 15 {
		case BKPT_EQ:
			return fmt.Sprintf("%#04x", uint32(arg))
		case SVC_EQ:
			return fmt.Sprintf("%#08x", uint32(arg))
		}
		return fmt.Sprintf("#%d", int32(arg))

	case ImmAlt:
		return fmt.Sprintf("#%d, %d", arg.Val, arg.Rot)

	case Mem:
		R := gnuArg(inst, -1, arg.Base)
		X := ""
		if arg.Sign != 0 {
			X = ""
			if arg.Sign < 0 {
				X = "-"
			}

	case arg_const:
		v := x & (1<<8 - 1)
		rot := (x >> 8) & (1<<4 - 1) * 2
		if rot > 0 && v&3 == 0 {
			// could rotate less
			return ImmAlt{uint8(v), uint8(rot)}
		}
		if rot >= 24 && ((v<<(32-rot))&0xFF)>>(32-rot) == v {
			// could wrap around to rot==0.
			return ImmAlt{uint8(v), uint8(rot)}
		}
		return Imm(v>>rot | v<<(32-rot))

	case arg_endian:
		return Endian((x >> 9) & 1)

	case arg_fbits:

		immhi := ((x >> 5) & (1<<19 - 1))
		immlo := ((x >> 29) & (1<<2 - 1))
		immhilo := (immhi)<<2 | immlo
		return PCRel((int64(immhilo) << 43) >> 43)

	case arg_slabel_immhi_immlo_12:
		immhi := ((x >> 5) & (1<<19 - 1))
		immlo := ((x >> 29) & (1<<2 - 1))
		immhilo := (immhi)<<2 | immlo
		return PCRel(((int64(immhilo) << 12) << 31) >> 31)

	case arg_Xns_mem:
		Rn := RegSP(X0) + RegSP(x>>5&(1<<5-1))