American Megatrends Super Voyager LPX, Руководство пользователя, Страница: 124 / 200

Chapter 4 VGA BIOS
118
Super VGA Functions,
Continued
Compatibility
The VESA INT 10h SVGA BIOS Extension preserve maximum
compatibility with the standard VGA environment. The VESA INT 10h
Super VGA BIOS extensions minimize the changes necessary to an
existing VGA BIOS. RAM-based and ROM-based SVGA BIOS
implementations are possible.
Standard VGA BIOS
The VESA INT 10g SVGA BIOS Extension minimize the effects on the
standard VGA BIOS. Standard VGA BIOS functions need to be
modified very little. Two standard VGA BIOS functions are affected by
the VESA INT 10h extension:
• Function 00h (Set video mode), and
• Function 0Fh (Read current video state).
VESA-aware applications do not set the video mode using INT 10h
function 00h and cannot INT 10h function 0Fh.
SVGA INT 10h functions 02h Set Super VGA mode and 03h Get Super
VGA mode are used instead.
VESA-unaware applications such as old programs with popup windows
and other TSRs and the DOS CLS command can use VGA BIOS
function 0Fh to get the present video mode and can call VGA BIOS INT
10h function 00h to restore or reinitialize the old video mode.
The value returned by INT 10h function 0Fh can be used to reinitialize
the video mode through INT 10h function 00h. The system BIOS must
track the last SVGA mode in effect.
Output functions such as TTY output, scroll, set pixel, etc. are supported
in SVGA modes.