Special Programming Information
*******************************
This information is intended for advanced programmers writing applications or
drivers to make use of the extended capabilities of the VGA Professional Card.
This information is not needed for normal use of the VGA Professional. Use of
the information contained here requires familiarity with assembly language
programming and the workings of the IBM PC/AT environments.

Programmers requiring additional general information on programming VGA may
want to refer to the IBM PS/2 Technical Reference manuals as well as the
following book: Programmer's Guide to PC and PS/2 Video Systems,
by Richard Wilton, Microsoft Press, 1987. (ISBN 1-55615-103-9). 

Programming Considerations
**************************
Refer to the Extended Video Mode table in the VGA Professional Card Software
Manual for a description of the extended video modes available on your VGA
Professional Card.

Extended 800x600 Graphics Modes hex 58,59
*****************************************
800 by 600 extended graphics modes require a multi-frequency monitor. No 
checking is done in the BIOS or hardware to determine if such a monitor is
connected.  This mode is available independent of the setting of the 
multi-frequency monitor special timing switch (switch lever 1).

Extended 256 Color Graphics Modes hex 5E, 5F
********************************************
The 640 by 480 and 640 by 400 extended graphics modes of the VGA Professional
Card can be invoked using the SetMode BIOS call.  The file 256COLOR.TXT on this
disk describes in detail how to access the additional memory required for these
extended modes.

Extended BIOS Calls
Setmode Extensions
******************
The extended video modes of the VGA Professional can be set via the standard
SETMODE BIOS call or through the SET SPECIAL MODE BIOS call. Additionally
support is provided for setting and locking non-VGA modes and reading and
writing the Paradise Registers through the EXTENDED FUNCTIONS Setmode BIOS call.

Setmode (BIOS call AH=00) has been extended as follows:

    AH = 00h    SETMODE
        AL = extended video mode
            This call will set the extended VGA Professional Card video modes:
            54h, 55h, 56h, 57h, 58h, 59h, 5Eh, 5Fh.

    AX = 007E   SET SPECIAL MODE 
                   This call sets modes by describing the mode desired.

       BX = The horizontal dimension of the mode desired
            (in pixels for graphics modes, columns for alpha modes) 
       CX = The vertical dimension of the mode desired
            (in pixels for graphics modes, rows for alpha modes)
       DX = The number of colors of the mode desired
            (use 0 for monochrome modes)

    On exit, the BH register will equal 7E if successful.


    AX = 007F   EXTENDED FUNCTIONS
           This call supports the following functions:        

       BH = 00  SET VGA OPERATION

       BH = 01  SET NON-VGA OPERATION
           Board must be set to a valid mode for non-VGA operation.
           Color modes (0,1,2,3,4,5,6) will set non-VGA CGA operation.
           Monochrome mode 7 will set non-VGA MDA/Hercules operation.

       BH = 02  QUERY MODE STATUS 

           On exit the following is returned:

                  BL = 0 if operating in VGA mode.
                  BL = 1 if operating in non-VGA mode
                  CH = Total video RAM size in 64k byte units.
                  CL = Video RAM used by the current mode.

       BH = 03  LOCKS CURRENT MODE
           Allows current mode (VGA or non-VGA) to survive re-boot.
 
    Paradise Register Extended Function Calls

       BH = 0A  WRITE PARADISE REGISTER 0 (3ce index A)
           BL = Value to set in the paradise register.

       BH = 0B  WRITE PARADISE REGISTER 1 (3ce index B)
           BL = Value to set in the paradise register.

       BH = 0C  WRITE PARADISE REGISTER 2 (3ce index C)
           BL = Value to set in the paradise register.

       BH = 0D  WRITE PARADISE REGISTER 3 (3ce index D)
           BL = Value to set in the paradise register.

       BH = 0E  WRITE PARADISE REGISTER 4 (3ce index E)
           BL = Value to set in the paradise register.

       BH = 0F  WRITE PARADISE REGISTER 5 (3ce index F)
           BL = Value to set in the paradise register.
                The high order 4 bits cannot be changed (SWITCHES).

       BH = 1A  READ PARADISE REGISTER 0 (3ce index A)

           On exit the following is returned:

               BL = Value of the paradise register.

       BH = 1B  READ PARADISE REGISTER 1 (3ce index B)

           On exit the following is returned:

               BL = Value of the paradise register.

       BH = 1C  READ PARADISE REGISTER 2 (3ce index C)

           On exit the following is returned:

               BL = Value of the paradise register.

       BH = 1D  READ PARADISE REGISTER 3 (3ce index D)

           On exit the following is returned:

               BL = Value of the paradise register.

       BH = 1E  READ PARADISE REGISTER 4 (3ce index E)

           On exit the following is returned:

               BL = Value of the paradise register.

       BH = 1F  READ PARADISE REGISTER 5 (3ce index F)

           On exit the following is returned:

               BL = Value of the paradise register.

    On exit, the BH register will equal 7F if successful.

Note: The state of Paradise Registers cannot be assumed between standard 
Setmode calls, and should not be assumed in general.