}
		j = delta
	}
	if x.before != magic32 || x.after != magic32 {
		t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magic32, magic32)
	}
}

func TestSwapInt32Method(t *testing.T) {
	var x struct {
		before int32
		i      Int32
		after  int32
	}
	x.before = magic32
	x.after = magic32
	var j int32
	for delta := int32(1); delta+delta > delta; delta += delta {

	if len(b) < len(magic32) || string(b[:len(magic32)]) != magic32 {
		return errors.New("hash/fnv: invalid hash state identifier")
	}
	if len(b) != marshaledSize32 {
		return errors.New("hash/fnv: invalid hash state size")
	}
	*s = sum32(byteorder.BeUint32(b[4:]))
	return nil
}

func (s *sum32a) UnmarshalBinary(b []byte) error {
	if len(b) < len(magic32a) || string(b[:len(magic32a)]) != magic32a {

		// must be converted to little endian first though.
		var buf [4]byte
		binary.BigEndian.PutUint32(buf[:], ff.Magic)
		leMagic := binary.LittleEndian.Uint32(buf[:])
		if leMagic == Magic32 || leMagic == Magic64 {
			return nil, ErrNotFat
		} else {
			return nil, &FormatError{0, "invalid magic number", nil}
		}
	}
	offset := int64(4)

	Magic  uint32
	Cpu    Cpu
	SubCpu uint32
	Type   Type
	Ncmd   uint32
	Cmdsz  uint32
	Flags  uint32
}

const (
	fileHeaderSize32 = 7 * 4
	fileHeaderSize64 = 8 * 4
)

const (
	Magic32  uint32 = 0xfeedface
	Magic64  uint32 = 0xfeedfacf
	MagicFat uint32 = 0xcafebabe
)

// A Type is the Mach-O file type, e.g. an object file, executable, or dynamic library.
type Type uint32

const (

	// Read and decode Mach magic to determine byte order, size.
	// Magic32 and Magic64 differ only in the bottom bit.
	var ident [4]byte
	if _, err := r.ReadAt(ident[0:], 0); err != nil {
		return nil, err
	}
	be := binary.BigEndian.Uint32(ident[0:])
	le := binary.LittleEndian.Uint32(ident[0:])
	switch Magic32 &^ 1 {
	case be &^ 1:
		f.ByteOrder = binary.BigEndian
		f.Magic = be
	case le &^ 1:

	machoMagicLittle := binary.LittleEndian.Uint32(header[:])
	machoMagicBig := binary.BigEndian.Uint32(header[:])

	if machoMagicLittle == macho.Magic32 || machoMagicLittle == macho.Magic64 ||
		machoMagicBig == macho.Magic32 || machoMagicBig == macho.Magic64 {
		f, err := b.openMachO(name, start, limit, offset)
		if err != nil {
			return nil, fmt.Errorf("error reading Mach-O file %s: %v", name, err)
		}

Russ Cox <******@****.***> 1629910106 -0400

// For 32-bit divides on 64-bit machines
// We'll use a regular (non-hi) multiply for this case.
(Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && umagic32(c).m&1 == 0 =>
  (Trunc64to32
    (Rsh64Ux64 <typ.UInt64>
      (Mul64 <typ.UInt64>
        (Const64 <typ.UInt64> [int64(1<<31+umagic32(c).m/2)])
        (ZeroExt32to64 x))
      (Const64 <typ.UInt64> [32+umagic32(c).s-1])))

	// cond: umagicOK32(c) && config.RegSize == 4 && umagic32(c).m&1 == 0 && config.useHmul
	// result: (Rsh32Ux64 <typ.UInt32> (Hmul32u <typ.UInt32> (Const32 <typ.UInt32> [int32(1<<31+umagic32(c).m/2)]) x) (Const64 <typ.UInt64> [umagic32(c).s-1]))
	for {
		x := v_0
		if v_1.Op != OpConst32 {
			break
		}
		c := auxIntToInt32(v_1.AuxInt)
		if !(umagicOK32(c) && config.RegSize == 4 && umagic32(c).m&1 == 0 && config.useHmul) {
			break

	m := M.Uint64()
	return umagicData{s: int64(s), m: m}
}

func umagic8(c int8) umagicData   { return umagic(8, int64(c)) }
func umagic16(c int16) umagicData { return umagic(16, int64(c)) }
func umagic32(c int32) umagicData { return umagic(32, int64(c)) }
func umagic64(c int64) umagicData { return umagic(64, c) }

// For signed division, we use a similar strategy.
// First, we enforce a positive c.