sr := io.NewSectionReader(r, 0, 1<<63-1)
	// Read XCOFF target machine
	var magic uint16
	if err := binary.Read(sr, binary.BigEndian, &magic); err != nil {
		return nil, err
	}
	if magic != U802TOCMAGIC && magic != U64_TOCMAGIC {
		return nil, fmt.Errorf("unrecognised XCOFF magic: 0x%x", magic)
	}

	f := new(File)
	f.TargetMachine = magic

	// Read XCOFF file header

	Fopthdr  uint16 // Number of bytes in optional header
	Fflags   uint16 // Flags
	Fnsyms   uint32 // Number of entries in symbol table
}

const (
	FILHSZ_32 = 20
	FILHSZ_64 = 24
)
const (
	U802TOCMAGIC = 0737 // AIX 32-bit XCOFF
	U64_TOCMAGIC = 0767 // AIX 64-bit XCOFF
)

// Flags that describe the type of the object file.
const (
	F_RELFLG    = 0x0001
	F_EXEC      = 0x0002
	F_LNNO      = 0x0004