uaddr := uintptr(unsafe.Pointer(addr))
	addr32 := (*uint32)(unsafe.Pointer(uaddr &^ 3))
	word := uint32(v) << ((uaddr & 3) * 8) // little endian
	for {
		old := *addr32
		if Cas(addr32, old, old|word) {
			return
		}
	}
}

//go:nosplit
func And8(addr *uint8, v uint8) {
	// Align down to 4 bytes and use 32-bit CAS.
	uaddr := uintptr(unsafe.Pointer(addr))
	addr32 := (*uint32)(unsafe.Pointer(uaddr &^ 3))

		case PrefixPT:
			op += ",pt"
			continue

		case PrefixAddrSize, PrefixAddr16, PrefixAddr32:
			// For unknown reasons, if the addr16 prefix is repeated,
			// libopcodes displays all but the last as addr32, even though
			// the addressing form used in a memory reference is clearly
			// still 16-bit.
			n := 32
			if inst.Mode == 32 {
				n = 16
			}
			numAddr++

	}
	if prefixBits&haveHintNotTaken != 0 {
		prefix += "hint-not-taken "
	}
	if prefixBits&haveAddr16 != 0 {
		prefix += "addr16 "
	}
	if prefixBits&haveAddr32 != 0 {
		prefix += "addr32 "
	}
	if prefixBits&haveData16 != 0 {
		prefix += "data16 "
	}
	if prefixBits&haveData32 != 0 {
		prefix += "data32 "
	}

	if inst.Op == 0 {
		if prefix == "" {
			return "<no instruction>"

	PrefixLOCK:     "LOCK",
	PrefixREP:      "REP",
	PrefixREPN:     "REPN",
	PrefixAddrSize: "ADDRSIZE",
	PrefixDataSize: "DATASIZE",
	PrefixAddr16:   "ADDR16",
	PrefixData16:   "DATA16",
	PrefixAddr32:   "ADDR32",
	PrefixData32:   "DATA32",
	PrefixBND:      "BND",
	PrefixXACQUIRE: "XACQUIRE",
	PrefixXRELEASE: "XRELEASE",
	PrefixREX:      "REX",
	PrefixPT:       "PT",
	PrefixPN:       "PN",
}