IBM PC CONVERTIBLE

091E 74 04
0920 B4 02
0922 CD 10
0924
0924
E9 016F R
0927
0927
0927
50
0928 B4 20
092A E8 0000
0920
A8 03
092F 58
0930 75 03
0932 E9 016F R
0935
3C 00
0937 75 5A
0939 B4 20
093B E8 0000
093E A8 01
0940 B8 B800
0943 75 03
0945 B8 BOOO
0948
0948
8E CO
094A OA FF
094C 74 43
094E 8A C7
JE
MOV
INT
DONE:
JMP
DONE
AH ,S ELCURSOR_POS
VIDEO_FN
VIDEO_RETURN
ENDP
ELSE RESTORE OLD CURSOR POS
RETURN TO CALLER
LCD_REQUEST
INPUT
OUTPUT
THESE ROUTINES PERFORM FUNCTIONS SPECIFIC TO THE LCD
CONTROLLER.
AL - LCD REQUEST NUMBER
o " LOAD USER SPECI FI ED FONT
1 " LOAD SYSTEM ROM DEFAULT FONT
2 " SET LCD HIGH INTENSITY ATTRIBUTE MAPPING
3 - 255 " NO OPERATION
(OS) " DATA SEGMENT
ADDITIONAL INPUTS ARE REQUIRED FOR EACH REQUEST
LCD MUST BE PRESENT. IF NOT, NO OPERATION IS PERFORMED
LCD SPECIFIC FUNCTION WILL BE PERFORMED IF A LCD
IS PRESENT
PUSH
MOV
CALL
TEST
POP
JFZ
JNZ
JMP
CMP
JNE
PROC NEAR
AX
AH, RTCDSP _CON
GELRTCREG ;
AL,
DSP _CLCD+DSP ~LCD
AX
V IDEO_RETURN
$+5
V IDEO_RETURN
AL,O
DEFONT
SAVE LCD_REQUEST
GET DISPLAY CONFIGURATION
RESTORE LCD REQUEST
LCD IS NOT AVAILABLE - EXIT
I F
NOT ZERO JUMP AROUND JUMP
ELSE TAKE A LONG JUMP
I F LOAD USER FONT REQUEST
LOAD_USERJONT
INPUT
THIS ROUTINE ACCESSES THE LCD FONT STORAGE AND ALTERS
ONE OR MORE CHARACTERS, ALLOWING THE USER TO CAUSE DIFF-
ERENT CHARACTERS TO BE DISPLAYED IN ALPHA/NUMERIC MODE
ES:DI - POINT TO CHARACTER FONT IN USER TABLE WHERE
LOADING IS TO START FROM
OUTPUT
CX - NUMBER OF CHARACTERS TO STORE (1-256) VALUE CHECKED
DL - CHAR OFFSET INTO RAM FONT AREA
BH - NUMBER OF BYTES PER CHARACTER (1-255) VALUE CHECKED
BL - 0 " LOAD MAIN FONT (BLOCK 0)
1 " LOAD ALTERNATE FONT (BLOCK 1)
2-255
" NO OPERATION
THE USER SPECI FI ED FONT IS LOADED
ALTERED CHARACTERS WILL DISPLAY DIFFERENTLY IN A/N MODE
INTERRUPTS:
DISABLED DURING THE LOADING OF THE FONT
MOV
CALL
TEST
MOV
JNZ
MOV
LCD 1 :
MOV
OR
JZ
MOV
AH, RTCDSP _CON
GELRTCREG
AL,DSP_CLCD
AX,CGA_RAM
LCDI
AX ,MONO_RAM
ES,AX
BH, BH
LCD3
AL,BH
; GET DISPLAY CONFIGURATION
USE CGA REGEN ADDRESS
IS LCD CONFIGURED AS CGA ?
NO, USE MONO REGEN ADDRESS
LCD REGEN ADDR IS FONT SEG "
DEST SEG FOR FONT MOVE
IS # OF BYTES PER CHAR> 0
NO, IT IS 0 THEN END
BYTES PER CHARACTER TIMES
2-112 ROM BIOS