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Subfunction: al = 23h (video) – Juniper Systems Allegro DOS Manual User Manual

Page 132

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132 Allegro DOS Owner’s Manual

Subfunction: AL = 1Ah/AL = 1Bh (set auto-panning off/on)
There is no output for these subfunctions. AL = 1Ah turns auto-
panning off. AL = 1Bh turns auto-panning on.

Subfunction: AL = 1Eh (read miscellaneous BIOS setup bytes)
Input: None

Output: AL = Miscellaneous System Setup Flags

Miscellaneous System Setup Flags Bit information:

bit 0

0 = reboot mode, 1 = suspend/resume mode

bit 1 reserved

bit

2

reserved

bit

3

reserved

bit

4

reserved

bit 5

0 = auto-panning active,

1 = auto-panning inactive

bit 6 reserved

bit 7 0 = black and white, 1 = gray scale (video)

Subfunction: AL = 23h (video)
This routine sets the display to black and white or to 64 gray shades.

BL =

00h

black and white 1

01h

gray

scale

(16

shades)

02h

black

and

white

2

03h

return current setting in AL

This function controls how the BIOS maps CGA colors to LCD gray
scale. B/W 1 and B/W 2 map all colors to either black on white or
white on black to increase viewability for some programs. B/W 1 is
faster than B/W 2 but only works on programs which go through the
BIOS for video text output. B/W 2 should work on all programs but
is less effi cient than B/W 1.

Note: This function is applicable only to text mode.