DOS Internal - Get directory entry

        Entry:
          AX = 150Fh
          CX = drive number (0=A:)
          ES:BX -> ASCIZ path name
          SI:DI -> 255-byte buffer for directory entry
        Return:
          CF set on error
            AX = error code
          CF clear if succesful
            AX = disk format (0=High Sierra,1=ISO 9660)

        Format of directory entry:
                Offset  Size    Description
                 00h    BYTE  length of directory entry
                 01h    BYTE  length of XAR in LBN's
                              (don't ask me what that means...)
                 02h    DWORD LBN of data, Intel (little-endian) format
                 06h    DWORD LBN of data, Motorola (big-endian) format
                 0Ah    DWORD length of file, Intal format
                 0Eh    DWORD length of file, Motorola format
                ---High Sierra---
                 12h  6 BYTEs date and time
                 18h    BYTE  bit flags
                 19h    BYTE  reserved
                ---ISO 9660---
                 12h  7 BYTEs date and time
                 19h    BYTE  bit flags
                ---both formats---
                 1Ah    BYTE  interleave size
                 1Bh    BYTE  interleave skip factor
                 1Ch    WORD  volume set sequence number, Intel format
                 1Eh    WORD  volume set sequence number, Motorola format
                 20h    BYTE  length of file name
                 21h  N BYTEs file name
                        BYTE (optional) padding if filename is odd length
                      N BYTEs system data