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X-Hacker.org- Assembly Language - <b>0:4a8h double-word pointer to video parameters for the ega</b>
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0:4A8h Double-Word Pointer to Video Parameters for the EGA
Length: 4 bytes
This double-word pointer points to a list of pointers that contain
various parameters and overrides for the Enhanced Graphics Adapter
(EGA).
--------------------------------------------------------------------------
Table Pointed to by Double-Word at 0:4A8h
Offset Size (bytes) Description
00h 4 Video Parameter Table Pointer
04h 4 Dynamic Save Area Pointer
08h 4 Alpha Mode Auxiliary Character Generator Pointer
0Ch 4 Graphics Mode Auxiliary Character Generator Pointer
10h 4 Reserved (always 00:00h)
14h 4 Reserved (always 00:00h)
18h 4 Reserved (always 00:00h)
--------------------------------------------------------------------------
Video Parameter Table Pointer (Double-Word)
This double-word pointer is initialized to point to the BIOS video
parameter table.
--------------------------------------------------------------------------
Dynamic Save Area Pointer (Double-Word)
This double-word pointer is optional, hence it is initialized to
00:00h. When used, this pointer points to a RAM table where specific
dynamic values are saved. Currently the values are defined as follows:
Offset Size (bytes) Description
00h 16 16 EGA palette register values
10h 1 Overscan value
11h 239 Reserved
--------------------------------------------------------------------------
Alpha Mode Auxiliary Character Generator Pointer (Double-Word)
This double-word pointer is optional; hence it is initialized to
00:00h. When used, this pointer points to a table as defined below:
Offset Size (bytes) Description
00h 1 Bytes per character
01h 1 Block to load (0=normal operation)
02h 2 Count to store (256=normal operation)
04h 2 Character offset (0=normal operation)
06h 4 Double-word pointer to Font Table
0Ah 1 Maximum displayable rows (If FFh,
maximum rows calculated)
0Bh n 'n' bytes consisting of different
mode values for this font.
(0FFh is terminator)
--------------------------------------------------------------------------
Graphics Mode Auxiliary Character Generator Pointer (double-word)
This double-word pointer is optional; hence it is initialized to
00:00h. When used, this pointer points to a table as defined below:
Offset Size (bytes) Description
00h 1 Displayable rows
01h 2 Bytes per character
03h 4 Double-word pointer to Font Table
07h n 'n' bytes consisting of different
mode values for this font.
(0FFh is terminator)
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