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Advanced BIOS Functions
6-24
CMD#
1 -
Display String Data on CRT
This command, like CMD# 0, displays the data addressed by LA and CA for the
length in NOC on the CRT. The display data must be in string data format with each
item consisting of one byte of normal character code data.
The contents of the display request block are the same for this command as for
CMD# 0, except that CMD # is 1.
CMD#
2 -
Report Cursor Position
This command returns the current cursor position in fields LA and CA in the display
request block. The function uses only the display request block fields listed below.
The contents of the remainder of the area are ignored.
CMD#
2
LA
Range is 0-24, binary.
CA
Range is 0-79, binary.
CMD# 3 - Roll Down Screen
This command enables the programmer to roll down the contents of video memory
a maximum of 25 lines on the screen, as shown in Figure 6-5. The function uses only
the display request block fields listed below. The contents of the remainder of the
area are ignored.
CMD#
3
LA
Number of lines to roll down (1-25, binary)
VIDLO MEMORY
DISPLA YLD SCREEN
29
0
CURSOR
NI:W
Figure 6-5 Roll Down Screen
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