for i, p := range inst.Prefix {
			if p == PrefixPT || p == PrefixPN {
				inst.Prefix[i] |= PrefixImplicit
			}
		}
	}

	switch inst.Op {
	case AAA, AAS, CBW, CDQE, CLC, CLD, CLI, CLTS, CMC, CPUID, CQO, CWD, DAA, DAS,
		FDECSTP, FINCSTP, FNCLEX, FNINIT, FNOP, FWAIT, HLT,
		ICEBP, INSB, INSD, INSW, INT, INTO, INVD, IRET, IRETQ,
		LAHF, LEAVE, LRET, MONITOR, MWAIT, NOP, OUTSB, OUTSD, OUTSW,

	"CMPSL",
	"CMPSQ",
	"CMPSS",
	"CMPSW",
	"CMPW",
	"CMPXCHG16B",
	"CMPXCHG8B",
	"CMPXCHGB",
	"CMPXCHGL",
	"CMPXCHGQ",
	"CMPXCHGW",
	"COMISD",
	"COMISS",
	"CPUID",
	"CQO",
	"CRC32B",
	"CRC32L",
	"CRC32Q",
	"CRC32W",
	"CVTPD2PL",
	"CVTPD2PS",
	"CVTPL2PD",
	"CVTPL2PS",
	"CVTPS2PD",
	"CVTPS2PL",
	"CVTSD2SL",
	"CVTSD2SQ",
	"CVTSD2SS",
	"CVTSL2SD",

	TR6:  "%tr6",
	TR7:  "%tr7",
}

var gnuOp = map[Op]string{
	CBW:       "cbtw",
	CDQ:       "cltd",
	CMPSD:     "cmpsl",
	CMPSD_XMM: "cmpsd",
	CWD:       "cwtd",
	CWDE:      "cwtl",
	CQO:       "cqto",
	INSD:      "insl",
	IRET:      "iretw",
	IRETD:     "iret",
	IRETQ:     "iretq",
	LODSB:     "lods",
	LODSD:     "lods",
	LODSQ:     "lods",
	LODSW:     "lods",
	MOVSD:     "movsl",