File Name String Parser - FNAME
FCB Initialization      - INITFCB
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FNAME - File Name String Parser

  ENTER: HL = Pointer to target string ending with delimiter
	 DE = Pointer to a 36-byte long FCB
  EXIT : BC = Disk/User
	      B=Disk (Drive A=1..P=16, 0FFH=No Disk specified)
	      C=User (0..31, '?'=All Users, 0FFH=No User spec)
	 HL = Pointer to the character which ended the scan
	  A <> 0, Zero Flag Clear (NZ) if String Parsed Ok
	      A = 0, Zero Set (Z) if invalid Disk or User
  USES : AF,BC,HL

 Usage:  This routine parses a string to a specified FCB, and
  Disk/User to Registers.  The string is assumed to be in form:

		DU:FILENAME.TYP

  where any part of the specification is optional.  It clears
  all bytes of the FCB to Zero except for the FN (File Name)
  and FT (File Type) fields which are initialized to values
  extracted from the string, or Spaces if absent.

  The string pointed to by HL is not a conventional string in
  the sense of the rest of the SYSLIB routines.  It is ended
  by any of the following delimiters, as opposed by simply
  always being terminated by a binary zero.  Delimiters are:

	<NULL or Binary 0>	<SP or Space>
	     =    _    ;    ,    <    >

 Examples:

	TEST.TXT    <-- FN=TEXT  FT=TXT, B = 0FFH, C = 0FFH

	A:T	    <-- FN=T  FT=<Saces>, B = 1, C = 0FFH

	5:T	    <-- FN=T  FT=<Saces>, B = 0FFH, C = 5

	C10:X.Y	    <-- FN=X  FT=Y, B = 3, C = 10

INITFCB - FCB Initialization

  ENTER: DE = Pointer to 36-byte FCB buffer
  EXIT : None
  USES : None

 Usage:  This routine is used as a general purpose application
  to clear all bytes in an FCB to Zero except for the File Name
  and Type fields.

  Note: Using INITFCB to prepare FCBs for use destroys any
  Drive specification in the first byte of the FCB since it
  will be set to Zero equating to the Currently Logged Drive.