a := inst.Args[i]
		if a == nil {
			continue
		}
		args = append(args, plan9Arg(&inst, pc, symname, a))
	}

	var rep string
	var last Prefix
	for _, p := range inst.Prefix {
		if p == 0 || p.IsREX() || p.IsVEX() {
			break
		}

		switch {
		// Don't show prefixes implied by the instruction text.
		case p&0xFF00 == PrefixImplicit:
			continue
		// Only REP and REPN are recognized repeaters. Plan 9 syntax

			switch p &^ PrefixIgnored {
			case PrefixData16, PrefixData32, PrefixCS, PrefixDS, PrefixES, PrefixSS:
				inst.Prefix[i] |= PrefixImplicit
			}
			if p.IsREX() {
				inst.Prefix[i] |= PrefixImplicit
			}
			if p.IsVEX() {
				if p == PrefixVEX3Bytes {
					inst.Prefix[i+2] |= PrefixImplicit
				}
				inst.Prefix[i] |= PrefixImplicit
				inst.Prefix[i+1] |= PrefixImplicit
			}
		}
	}

	PrefixVEX3Bytes Prefix = 0xC4 // Long form of vex prefix
)

// IsREX reports whether p is a REX prefix byte.
func (p Prefix) IsREX() bool {
	return p&0xF0 == PrefixREX
}

func (p Prefix) IsVEX() bool {
	return p&0xFF == PrefixVEX2Bytes || p&0xFF == PrefixVEX3Bytes
}

func (p Prefix) String() string {
	p &^= PrefixImplicit | PrefixIgnored | PrefixInvalid
	if s := prefixNames[p]; s != "" {
		return s
	}

		implicitData = false
	)
	for _, p := range inst.Prefix {
		if p&0xFF == PrefixDataSize && p&PrefixImplicit != 0 {
			implicitData = true
		}
	}
	for _, p := range inst.Prefix {
		if p == 0 || p.IsVEX() {
			break
		}
		if p&PrefixImplicit != 0 {
			continue
		}
		switch p &^ (PrefixIgnored | PrefixInvalid) {
		default:
			if p.IsREX() {
				if p&0xFF == PrefixREX {
					prefix += "rex "