The 4-byte pointer at 0040:00a8 has been named SAVE_PTR by an imaginative
 programmer.  It points to a table of EGA/VGA data block pointers.  You can
 change this address to point to a different data area in which you define
 your own fonts and other options.

 To make a change, copy the current table and then modify the copy.  You
 can use TSR techniques to make your customized table resident in memory to
 enable it with each mode change.

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   +0      4  pfrVidParms  addr of a table of EgaVidParmsRec structures
   +4      4  pfrDynParms  addr of an EgaDynamicSaveRec or 0:0
   +8      4  pfrTxtAuxFnt addr of an EgaTxtFontRec structure or 0:0
  +0cH     4  pfrGfxAuxFnt addr of an EgaGfxFontRec structures or 0:0
  +10H     4  pfrSavePtr2  (VGA only) addr of a VgaSavePtr2Rec or 0:0
  +14H     8  res          reserved (two far pointers)
          28               size of an EgaSavePtrRec structure

 pfrVidParms  This MUST exist.  It is initially set to point to a table in
              ROM.  The table should be 1472 bytes long,  with 64 bytes for
              each of 23 (17H) different video modes.  In this parameter
              table: Modes 0-10H are the modes listed in Video Modes for 64K
              EGAs.  Modes 11H-12H are for 350-line graphics with 128K+ RAM
              on board.  Modes 13H-17H are the 350-line versions of text
              modes 0-3 when used with the Enhanced Color Display.

              See EgaVidParmsRec for the layout.

 pfrDynParms  Initially 0000:0000 (not used).  When present, this points to
              an EgaDynamicSaveRec to hold the current settings for EGA and
              VGA palettes.  This is updated when the BIOS updates the
              Attribute Controller registers (as in INT 10H 1000H).

pfrTxtAuxFnt  Initially 0000:0000 (not used).  When present, this points to
              an EgaTxtFontRec structure that overrides all or part of the
              font definition for specified text modes; the font will be
              loaded to the character generator when selected text modes are
              initialized.  You can use this vector to setup unusual and
              exotic fonts or to override just a few characters for national
              language support.

              On VGAs, an additional character set may be set up for
              selected modes by setting up a VgaSavePtr2Rec.

pfrGfxAuxFnt  Initially 0000:0000 (not used).  When present, this points to
              an EgaGfxFontRec structure.  The font information will be used
              to generate characters is specified graphics modes.

 pfrSavePtr2  This field contains an address on VGAs only.  It points to a
              VgaSavePtr2Rec which sets special options foe VGA video

See Also: EGA Data Areas
          EGA I/O Ports