IPV6_RECVERR                                = 0x19
	IPV6_RECVERR_RFC4884                        = 0x1f
	IPV6_RECVFRAGSIZE                           = 0x4d
	IPV6_RECVHOPLIMIT                           = 0x33
	IPV6_RECVHOPOPTS                            = 0x35
	IPV6_RECVORIGDSTADDR                        = 0x4a
	IPV6_RECVPATHMTU                            = 0x3c

	ACASD:   3<<30 | 0x45<<21 | 0x1f<<10,
	ACASW:   2<<30 | 0x45<<21 | 0x1f<<10,
	ACASH:   1<<30 | 0x45<<21 | 0x1f<<10,
	ACASB:   0<<30 | 0x45<<21 | 0x1f<<10,
	ACASAD:  3<<30 | 0x47<<21 | 0x1f<<10,
	ACASAW:  2<<30 | 0x47<<21 | 0x1f<<10,
	ACASLD:  3<<30 | 0x45<<21 | 0x3f<<10,
	ACASLW:  2<<30 | 0x45<<21 | 0x3f<<10,
	ACASALD: 3<<30 | 0x47<<21 | 0x3f<<10,
	ACASALW: 2<<30 | 0x47<<21 | 0x3f<<10,
	ACASALH: 1<<30 | 0x47<<21 | 0x3f<<10,

	{AXORB, yxorb, Pb, opBytes{0x34, 0x80, 06, 0x30, 0x32}},
	{AXORL, yaddl, Px, opBytes{0x83, 06, 0x35, 0x81, 06, 0x31, 0x33}},
	{AXORPD, yxm, Pe, opBytes{0x57}},
	{AXORPS, yxm, Pm, opBytes{0x57}},
	{AXORQ, yaddl, Pw, opBytes{0x83, 06, 0x35, 0x81, 06, 0x31, 0x33}},
	{AXORW, yaddl, Pe, opBytes{0x83, 06, 0x35, 0x81, 06, 0x31, 0x33}},
	{AFMOVB, yfmvx, Px, opBytes{0xdf, 04}},
	{AFMOVBP, yfmvp, Px, opBytes{0xdf, 06}},

	case 9: /* RLDC Ra, $sh, $mb, Rb */
		sh := uint32(p.RestArgs[0].Addr.Offset) & 0x3F
		mb := uint32(p.RestArgs[1].Addr.Offset) & 0x3F
		o1 = AOP_RRR(c.opirr(p.As), uint32(p.From.Reg), uint32(p.To.Reg), (uint32(sh) & 0x1F))
		o1 |= (sh & 0x20) >> 4 // sh[5] is placed in bit 1.
		o1 |= (mb & 0x1F) << 6 // mb[0:4] is placed in bits 6-10.
		o1 |= (mb & 0x20)      // mb[5] is placed in bit 5

   * of reads and delaying a lock acquisition until the threshold is crossed or a mutation occurs.
   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this

   * of reads and delaying a lock acquisition until the threshold is crossed or a mutation occurs.
   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this

	0x42, 0x88, 0x21, 0xc4, 0x00, 0x00, 0x14, 0x00,
	0xeb, 0xff, 0x42, 0x88, 0x21, 0xc4, 0x00, 0x00,
	0x14, 0x00, 0xeb, 0xff, 0x42, 0x88, 0x21, 0xc4,
	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00,
	0x00, 0xff, 0xff, 0x00, 0x17, 0x00, 0xe8, 0xff,
	0x42, 0x88, 0x21, 0xc4, 0x00, 0x00, 0x00, 0x00,
	0xff, 0xff, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00,
	0x17, 0x00, 0xe8, 0xff, 0x42, 0x12, 0x46, 0x16,