American Megatrends Super Voyager LPX, User Manual

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Chapter 4 VGA BIOS
132
Super VGA Functions,
Continued
Function 07h Subfunction 00h Set Display Start
This function selects the pixel to be displayed in the upper left corner of
the display from the logical page. This function can be used to pan and
scroll around logical screens that are larger than the displayed screen.
This function can also be used to rapidly switch between two different
displayed screens for double buffered animation effects.
Input: AH = 4Fh SVGA Support
AL = 07h Display Start Control
BH = 00h Reserved, must be 0.
BL = 00h Set Display Start
CX = First Displayed Pixel in Scan Line
DX = First Displayed Scan Line
Output: AX = Status
Function 07h Subfunction 01h Return Display Start
Input:
AH = 4Fh SVGA Support
AL = 07h Display Start Control
BL = 01h Return Display Start
Output: AX = Status
BH = 00h Reserved, set to 0.
CX = First Displayed Pixel in Scan Line
DX = First Displayed Scan Line
This function is also valid in text modes. In text modes, the application
should find the current character cell width through INT 10h Function
01h Return Super VGA Mode Information, multiply that times the
desired starting character column, and pass that value in the CX register.
It should also multiply the current character cell height times the desired
starting character row and pass that value in DX.