//       (64-UInt(immh:immb)) when immh = 01xx
//       (128-UInt(immh:immb)) when immh = 1xxx
//
// - arg_immediate_index_Q_imm4__imm4lt20gt_00__imm4_10:
//     the lowest numbered byte element to be extracted, encoded in the "Q:imm4" field.
//     It can have the following values:
//       imm4<2:0> when Q = 0, imm4<3> = 0
//       imm4 when Q = 1, imm4<3> = x
//
// - arg_sysop_AT_SYS_CR_system:

		case xArgImm8:
			inst.Args[narg] = Imm(imm8)
			narg++

		case xArgImm8u:
			inst.Args[narg] = Imm(uint8(imm8))
			narg++

		case xArgImm16:
			inst.Args[narg] = Imm(int16(imm))
			narg++

		case xArgImm16u:
			inst.Args[narg] = Imm(uint16(imm))
			narg++

		case xArgImm32:
			inst.Args[narg] = Imm(int32(imm))
			narg++

		case xArgImm64:

			return ImmAlt{uint8(v), uint8(rot)}
		}
		return Imm(v>>rot | v<<(32-rot))

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

	case arg_fbits:
		return Imm((16 << ((x >> 7) & 1)) - ((x&(1<<4-1))<<1 | (x>>5)&1))

	case arg_fp_0:
		return Imm(0)

	case arg_imm24:
		return Imm(x & (1<<24 - 1))

	case arg_imm5:
		return Imm((x >> 7) & (1<<5 - 1))

	case arg_imm5_32:

	o1 |= uint32(p.To.Reg&0x1f) << 21                         // T
	o1 |= uint32(p.From.Offset&0x1) << 17                     // IX
	o0 |= uint32((p.RestArgs[0].Addr.Offset>>16)&0xffff) << 0 // imm0
	o1 |= uint32(p.RestArgs[0].Addr.Offset&0xffff) << 0       // imm1
	out[1] = o1
	out[0] = o0
}

// xxspltiw XT,IMM32
func type_xxspltiw(c *ctxt9, p *obj.Prog, t *Optab, out *[5]uint32) {
	o0 := GenPfxOpcodes[p.As-AXXSPLTIW]

		buf.WriteString(opName)
		l := inst.Args[3].(Imm)
		if l == 0 {
			// L == 0 is an extended mnemonic for the same.
			asm := fmt.Sprintf(" %s,%s,%s",
				gnuArg(&inst, 0, inst.Args[0], PC),
				gnuArg(&inst, 1, inst.Args[1], PC),
				gnuArg(&inst, 2, inst.Args[2], PC))
			buf.WriteString(asm)
			startArg = 4
		}

	case "sync":
		lsc := inst.Args[0].(Imm)<<4 | inst.Args[1].(Imm)
		switch lsc {
		case 0x00:

	switch a := arg.(type) {
	case Imm:
		return fmt.Sprintf("$%d", uint32(a.Imm))

	case Imm64:
		return fmt.Sprintf("$%d", int64(a.Imm))

	case ImmShift:
		if a.shift == 0 {
			return fmt.Sprintf("$%d", a.imm)
		}
		return fmt.Sprintf("$(%d<<%d)", a.imm, a.shift)

	case PCRel:
		addr := int64(pc) + int64(a)

	ROTRV	R16, R9		// 02094856

//	LSHW imm ',' sreg ',' rreg
//	{
//		outcode(int($1), &$2, int($4), &$6);
//	}
	SLL	$19, R22, R21	// 0016acc0
	SLLV	$19, R22, R21	// 0016acf8
	SRL	$31, R6, R17	// 00068fc2
	SRLV	$31, R6, R17	// 00068ffa
	SRA	$8, R8, R19	// 00089a03
	SRAV	$19, R8, R7	// 00083cfb
	ROTR	$12, R8, R3	// 00281b02
	ROTRV	$8, R22, R22	// 0036b23a

//	LSHW imm ',' rreg
//	{

				}
			}
		}
	}

	switch inst.Op {
	case AAM, AAD:
		if imm, ok := iargs[0].(Imm); ok {
			if inst.DataSize == 32 {
				iargs[0] = Imm(uint32(int8(imm)))
			} else if inst.DataSize == 16 {
				iargs[0] = Imm(uint16(int8(imm)))
			}
		}

	case PUSH:
		if imm, ok := iargs[0].(Imm); ok {
			iargs[0] = Imm(uint32(imm))
		}
	}

	for _, p := range inst.Prefix {
		if p&PrefixImplicit != 0 {

			}
		}
	}
}

// An Imm is an integer constant.
type Imm struct {
	Imm     uint32
	Decimal bool
}

func (Imm) isArg() {}

func (i Imm) String() string {
	if !i.Decimal {
		return fmt.Sprintf("#%#x", i.Imm)
	} else {
		return fmt.Sprintf("#%d", i.Imm)
	}
}

type Imm64 struct {
	Imm     uint64
	Decimal bool
}

func (Imm64) isArg() {}

			op = "int3"
		}

	case CMPPS, CMPPD, CMPSD_XMM, CMPSS:
		imm, ok := inst.Args[2].(Imm)
		if ok && 0 <= imm && imm < 8 {
			inst.Args[2] = nil
			op = cmppsOps[imm] + op[3:]
		}

	case PCLMULQDQ:
		imm, ok := inst.Args[2].(Imm)
		if ok && imm&^0x11 == 0 {
			inst.Args[2] = nil
			op = pclmulqOps[(imm&0x10)>>3|(imm&1)]
		}

	case XLATB:
		if markLastImplicit(&inst, PrefixAddrSize) {