IBM PC CONVERTIBLE

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VIDEO_IO
THESE ROUTINES PROVIDE THE CRT INTERFACE
THE FOLLOWI NG FUNCTIONS ARE PROV I OED:
(AH) =OOH SET MODE (AL) CONTAINS MODE VALUE
TYPE RES/DIM DISPLAY MAX PAGES NOTES
(AL)=O ALPHA 40X25 COLOR -
BW**
8
(AL)
=1 ALPHA 40X25 COLOR 8
(AL)=2
ALPHA 80X25 COLOR -
BW**
4
(AL)
=3 ALPHA 80X25 COLOR 4
*
DEFAULT
(AL)=4 GRAPHICS 320X200 COLOR 1
(AL)
=5
GRAPHICS 32DX200 COLOR - BW 1
(AL)
=6
GRAPHICS 640X200 COLOR - BW 1
(AL)
=7 ALPHA 80X25 MONOCHROME
1/4
*
INTERNAL
NOTE: IF HIGH BIT OF AL IS SET, THE REGEN BUFFER IS NOT CLEARED.
FOR MONOCHROME, CRT MODE WILL INTERNALLY DEFAULT TO 7.
FOR MONO ON LCD THE MAXIMUM PAGES ALLOWED IS 4, OTHERWISE
THE MAXIMUM PAGES ALLOWED IS 1.
FOR COLOR, AL=(7-255) WILL DEFAULT TO MODE 3
BW MODES OPERATE SAME AS COLOR MODES, BUT COLOR BURST IS
NOT ENABLED
(AH)=OlH SET CURSOR TYPE
(CH) = BITS 4-0 = START LINE FOR CURSOR
** HARDWARE WILL ALWAYS CAUSE BLINK
** SETTING BIT 5 OR 6 WILL CAUSE ERRATIC
** BLINKING OR NO CURSOR AT ALL
(CL) BITS 4-0 = END LINE FOR CURSOR
(AH)=02H SET CURSOR POSITION
(BH) = PAGE NUMBER (MUST BE 0 FOR GRAPHICS MODES)
(DH,DL) = ROW,COLUMN (0,0) IS UPPER LEFT
ROW = (0 - 24), COL = (0 - (CRT COLUMNS-i))
CRT COLUMNS IS EITHER 80 OR 40
(AH)=03H READ CURSOR POSITION
(BH) = PAGE NUMBER (MUST BE 0 FOR GRAPHICS MODES)
ON EXIT:
(DH,DL) =
ROW,COLUMN OF CURRENT CURSOR
(CH,CL) = CURSOR MODE CURRENTLY SET
(AH)=04H READ LIGHT PEN POSITION
ON EXIT:
(AH) = 0 -- LIGHT PEN SWITCH NOT DOWN/NOT TRIGGERED
(AH) = 1 -- VALID LIGHT PEN VALUE IN REGISTERS
(DH,DL) = ROW,COLUMN OF CHARACTER LP POSN
(CH) = RASTER LINE (0-199)
(BX) = PIXEL COLUMN (0-319,639)
(AH)=05H SELECT ACTIVE DISPLAY PAGE(VALID ONLY FOR ALPHA MODES)
(AL)=NEW PAGE VALUE
VALID PAGE VALUES: ALSO, SEE AH=OOH FOR PAGE INFO
MODES 0 & 1 - (0 - 7)
MODES 2 & 3 - (0 - 3)
MODE 7 0
MODE 7 & LCD CONFIGURED AS MONO - (0 - 3)
(AH)=06H
SCROLL ACTIVE PAGE UP
(AL) = NUMBER OF LINES, INPUT LINES BLANKED AT BOTTOM
OF WINDOW
AL = 0 MEANS BLANK ENTIRE WINDOW
(CH,CL) = ROW,COLUMN OF UPPER LEFT CORNER OF SCROLL
(DH,DL) = ROW,COLUMN OF LOWER RIGHT CORNER OF SCROLL
(BH) = ATTRIBUTE TO BE USED ON BLANK LINE
ROM BIOS 2-79