HP Vectra Technical Reference Manual page 40

Scan line is multiple of 4 (0,4,8,12 ) use offset 0
Scan line is multiple of 4 plus 1 (1,5,9,13 ) use offset 2000H
Scan line is multiple of 4 plus 2 (2,6,10,14 ) use offset 4000H
Scan line is multiple of 4 plus 3 (3,7,11,15 ) use offset 6000H
All the scan lines of a particular group are organized sequentially within a particular offset. See
Figures 3.2 and 3.3.
Other video driver data structures are located in the STD-BIOS data area. They are stored in
memory addresses 449H (40H:49H) through 466H (40H:66H). Table 3.1 lists the memory
locations and their definitions.
Table 3.1
5TD-8105 Video Driver Data Area
Address Type Definition
00449H
Byte Current Video Display Mode
0044AH
Word
Number of columns
0044CH
Word Regen buffer length
0044EH
Word
Starting address of regen buffer
00450H
Word Cursor position for Display Page 0
00452H
Word Cursor position for Display Page 1
00454H
Word Cursor position for Display Page 2
00456H
Word Cursor position for Display Page 3
00458H
Word
Cursor position for Display Page 4
0045AH
Word
Cursor position for Display Page 5
0045CH
Word Cursor position for Display Page 6
0045EH
Word Cursor position for Display Page 7
00460H
Word
Current cursor mode
00462H
Byte Active page number
00463H
Word
Address of current display adapter
00465H
Byte Mode (current setting of status register)
00466H
Byte
Pallet setting
Video data structures are also maintained in the EX-BIOS data area. These structures are
accessible through the data segment of the EX-BIOS video service routine. The following code
sets the ES register to the EX-BIOS video driver's (V_SVIDEO'S) data segment:
Video 31