Tseng Qtec VGA 1024, Installation Manual

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USING 132- AND 80-COLUMN TEXT MODES
This application note describes how to select the Qtec VGA1024
board's 132-column text modes from application programs and how
the 132-column text modes memory map is organized.
S electing 132- and 8Q-Column Color or Monochrome Text Modea
The Qtec VGA1024 board BIOS supports the following 132- and
80-column text modes on variable-frequency monitors. These modes
are not used by the IBM EGA. 132-column modes are not supported
on the IBM 8503, 8512, 8513, and 8514 analog monitors. The
numbers are in decimal except as noted.
Mode
Columns Rows Length of Memory Map
22 hex
132 44 132x44x2 = 11616 = 2D60 hex
23 hex
132 25 132x25x2 = 6600 = 19C8 hex
24 hex 132 28 132x28x2 = 7392 = 1CEO hex
*18 hex
132 44 132x44x2 = 11616 = 2D60 hex
*19 hex 132
25 132x25x2 = 6600 = 19C8 hex
*1A hex 132 28 132x28x2 = 7392 = 1CE0 hex
26 hex 80 60 80x60x2 = 9600 = 2580 hex
* 132-column monochrome modes
The 132-column modes are selected exactly as the standard modes
0-7 and D-12 are selected:
Place a 0 in register AH to indicate "select mode" function
. Place the mode number in register AL
. Execute an INT 10H instruction, generating software
interrupt 10 hex, which invokes the Qtec VGA1024 BIOS to
set the mode
The above calling sequence should be familiar to anyone who has
ever called the BIOS from assembly language or from a machine-
language driver, and is the standard BIOS interface for video mode
select.
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