The following statements reverse bit order for big and little endian longs. Test them with your data to see which one is required.

    #!/usr/bin/perl -l

    use strict;

    my $dword = pack "N", 0x01020304;

    print unpack "V", pack "b8b8b8b8", unpack "B8B8B8B8", $dword;
    print unpack "N", pack "b8b8b8b8", unpack "B8B8B8B8", $dword;
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If this doesn't work could you give an example of four bytes that you read and the integer that you expect.

--
John.