Compatibility: 1.0+
Expects: AH    29H
AL    bit-flags to select parsing options (see below)
DS:SI address of source text line to parse
ES:DI address of buffer to hold resulting unopened FCB
Returns: AL    0    if result FCB has no wildcard characters
1    if result FCB does contain wildcards 
0ffH if invalid drive ID in filespec
DS:SI updated: points to the character just past the filename
ES:DI preserved: points to the unopened FCB
Info: Creates an unopened FCB from a text line or command parameter.
The text starting at DS:SI is parsed for a filespec in the format
D:FILENAME.EXT and the buffer at ES:DI is filled in as a
properly-formatted, unopened FCB.

     This Fn is NOT useful for a text line containing a pathname.
Basically, this is a quick way to skip leading spaces, upshift
and remove the dot (.) from a filename input from the keyboard.
It converts * into a series of ?s and it allows you to pre-set a
default in the destination FCB (e.g., extension = "WKS").

The parsing action depends upon these bit flags in AL:
 7 6 5 4 3 2 1 0 
 0 0 0 0         
                  bit                                  mask value
          0: 1=scan off leading separators     (a | 01H)
          1: 1=use FCB drive byte as a default (a | 02H)
          2: 1=use FCB filename as a default   (a | 04H)
          3: 1=use FCB extension as a default  (a | 08H)

See Also: Fn 60H (Get Truename)
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DOS Fn 29H: Parse Filename