Function 4301h          Set File Attributes

    Sets the attributes for a specified file or directory.

        Entry   AX    = 4301h
                CX    = Desired attributes
                DS:DX = Pointer to filespec (ASCIIZ string)

        Return  AX = Error code, if CF is set
                     | 01h Invalid function code
                     | 02h File not found
                     | 03h Path not found
                     | 05h Access denied

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    The file specification must be a valid DOS file name or directory
    name and cannot contain wildcards.

    The file attributes in the CX register can be a combination
    (OR'ed) of the following values:

                attr_normal     = 00h
                attr_readonly   = 01h
                attr_hidden     = 02h
                attr_system     = 04h
                attr_archive    = 20h

    Only attr_hidden and attr_system are meaningful for directories.

    Bits 6 and 7 of the attribute byte are reserved and must be zero
    (values larger than 3Fh should not be specified).