IBM PC CONVERTIBLE - Page 119

037B 8A 08
MaV BL,AL
LI N E COUNT TO BL
0370 80 FC 04
CMP AH,4
TEST FOR GRAPHICS
0380 72 08
JC N12
0382 80 FC 07
CMP AH,7
TEST FOR MONO CARD
0385 74 03
JE N12
0387 E9 0533 R
JMP GRAPH I CS_DOWN
038A
N12 :
CONTI NU E_DOWN
038A 53
PUSH BX
SAVE ATTRIBUTE IN BH
038B 8B C2
MOV AX, OX
LOWER RIGHT CORNER
0380 E8 0343 R
CALL SCROLL_POS ITI ON
GET REGEN LOCATION
0390 74 20
JZ N16
0392 2B FO
SUB
SI,AX SI IS FROM ADDRESS
0394 8A E6
MOV
AH,DH GET TOTAL # ROWS
0396 2A E3
SUB AH,BL
COUNT TO MOVE IN SCROLL
0398
N13 :
0398 E8 036A R CALL
NI0
MOVE ONE ROW
039B 2B F5
SUB SI, BP
0390 2B FD
SUB
01, BP
039F FE CC
DEC
AH
03Al 75 F5
JNZ
N13
03A3
N14:
03A3
58 POP
AX RECOVER ATTRI BUTE
IN AH
03A4 BO 20
MOV
AL, '
03A6
N15 :
03A6
E8 0373 R
CALL NIl
CLEAR ONE ROW
03A9 2B FD
SUB 01, BP
GO TO N EXT ROW
03A8
FE CB
DEC BL
03AD
75 F7
JNZ N15
03AF
E9 032B R
JMP N5 SCROLL_END
03B2
N16 :
03B2 8A DE
MOV
BL,DH
03B4 EB ED
JMP N14
03B6 SCROLL_DOWN
ENDP
------------------------------- --- - - - - - - - - - - - - - - - - - - - - --
READ--'lLCURRENT
THIS ROUTINE READS THE ATTRIBUTE AND CHARACTER
AT THE CURRErn CURSOR POSITION AND RETURNS THEM
TO THE CALLER
INPUT
(BH) = DISPLAY PAGE ( ALPHA MODES ONLY
(AH) = CURRENT CRT MODE
(OS) = DATA SEGMENT
( ES)
= REGEN SEGMENT
OUTPUT
(AL)
= CHAR READ
(AH)
= ATTRI BUTE READ
INTERRUPTS: DISABLED DURING THE READ
------------------------ -- - - - - -- -------------------- ----
ASSUME
CS: ROMCODE, OS: DATA, ES: DATA
03B6 READ--'lLCURRENT PROC
NEAR
03B6
80 FC 04
CMP AH,4
IS THIS GRAPHICS
03B9 72 08 JC PI
03BB 80 FC 07 CMP AH,7
IS THIS MONO CARD
03BE 74 03 JE PI
03CO E9 066F R JMP GRAPH I CS_READ
03C3 PI:
READ--'lLCONTI NUE
03C3 E8 03EO R
CALL
FIND_POSITION
03C6 8B F3 MOV
SI, BX ESTABLISH ADDRESSING
IN SI
;----- WAIT FOR HORIZONTAL RETRACE
03C8 8B 16 0063
MaV
OX ,ADDR_6845
GET BASE ADDRESS
03CC
83 C2 06 ADD
DX,6 POINT AT STATUS PORT
03CF
06 PUSH ES
0300
IF POP OS
GET SEGMENT FOR QUICK ACCESS
0301
P2 : WAIT FOR RETRACE LOW
0301
EC IN AL,DX GET STATUS
0302 A8 01
TEST
AL,HORLRETRACE IS HORZ RETRACE LOW
0304 75 FB
JNZ P2
WAIT UNTIL IT IS
0306
FA
CLI
NO MORE INTERRUPTS
0307
P3:
WAIT FOR RETRACE HIGH
0307
EC IN
AL,DX GET STATUS
2-94 ROM BIOS