Specifications

103
Extended BIOS Calls (INT 10h)
These calls are spedtic to the WD-BIOS.
The following lists functions that are supported by the WD-BIOS with call
and return codes.
6.2.2
AX = 7F7Fh BH = 00h set non-VGA mode
AX = 7F7Fh BH = 01h set VGA mode
AX = 7F7Fh BH = 02h read spedtic status information
CH= number of available 64 KB blocks of screen memory
CL= number of used blocks
AX = 7F7Fh BH = 03h disable current VGA mode
BL= enable/disable current VGA mode
AX = 7F7Fh BH = 04h set non-VGA MDA (monochrome) mode
AX = 7F7Fh BH = 05h set non-VGA CGA (color) mode
AX = 7F7Fh BH = 06h set VGA monochrome mode
AX = 7F7Fh BH = 07h set VGA color mode
AX = 7F7Fh BH = 08h disable RAMDAC
BL= enable/disable RAMDAC
AX = 7F7Fh BH = 22h read BitBLT scroll status information
BL= hardware BitBLT or software scroll-function
0: hardware BitBLT scroll-function
1: software scroll-function
AX = 7F7Fh BH = 23h set BitBLT scroll-function
BL= 0: hardware BitBLT scroll-function
1: software scroll-function
AX = 7F7Fh BX = 4100h enable LCD- and CRT-monitor
AX = 7F7Fh BX = 4101h enable or disable auto-centering
This function is not available if vertical expansion
is actived.
AX = 7F7Fh BX = 4102h toggle vertical expansion
This function is available for video modes 3+ and
7+ only.