IBM PC CONVERTIBLE - Page 117

02E6
02E6
53
02E7 8B 08
02E9 8A C4
02EB F6 26 004A
02EF 32 FF
02F1 03 C3
02F3 01 EO
02F5 5B
02F6 C3
02F7
02F7
02F7
8A 08
02F9 80 FC 04
02FC
72 08
02FE 80 FC 07
0301 74 03
0303 E9 04DA R
0306
0306
53
0307
8B C1
0309 E8 0343
030C 74 31
030E
03 FO
0310 8A E6
0312 2A E3
0314
0314
E8 036A R
0317
03 F5
0319 03 FD
031B FE CC
0310
75 F5
031F
031F
58
0320 BO 20
0322
0322
E8 0373
0325 03 FD
0327 FE CB
0329 75 F7
0328
032B E8 0000 E
032E 80 3E 0049
0333 74 07
0335 AO 0065 R
0338
BA 0308
033B EE
033C
POSITION
INPUT
OUTPUT
THIS SERVICE ROUTINE CALCULATES THE REGEN
BUFFER ADDRESS OF A CHARACTER IN THE ALPHA MODE
AX = ROW, COLUMN POSITION
AX = OFFSET OF CHAR POSITION IN REGEN BUFFER
POSITION
PUSH
MOV
MOV
MUL
XOR
ADD
SAL
POP
RET
POSITION
BX
BX,AX
AL,AH
PROC NEAR
BYTE PTR CRLCOLS
BH,BH
AX,BX
AX,l
BX
ENDP
SAVE REGISTER
ROWS TO AL
DETERMI NE BYTES TO ROW
ADD IN COLUMN VALUE
* 2 FOR ATTRI BUTE BYTES
SCROLL UP
INPUT
OUTPUT
R 07
THIS ROUTINE MOVES A BLOCK OF CHARACTERS UP
ON THE SCREEN
(AL) = NUMBER OF ROWS TO SCROLL
(CX) = ROW/COLUMN OF UPPER LEFT CORNER
(OX) = ROW/COLUMN OF LOWER RIGHT CORNER
(BH) = ATTRIBUTE TO BE USED ON BLANKED LINE
(AH) = CURRENT CRT MODE
(OS) = DATA SEGMENT
(ES) = REGEN BUFFER SEGMENT
NONE -- THE REGEN BUFFER IS MODIFIED
ASSUME CS: ROMCODE, OS: DATA, ES: DATA
SCROLL_UP
PROC NEAR
MOV BL,AL
SAVE LINE COUNT IN BL
CMP AH,4
TEST FOR GRAPH I CS MODE
JC N1
HANDLE SEPARATELY
CMP AH,7
TEST FOR MONO CARD
JE N1
JMP GRAPH I CS_UP
N1 : UP_CONTINUE
PUSH 8X
SAVE FILL ATTRIBUTE IN BH
MOV AX,CX
UPPER LEFT POSITION
CALL SCROLLPOSITION
DO SETUP FOR SCROLL
JZ N7
BLANICFI ELD
ADD SI,AX
FROM ADDRESS
MOV AH,DH
# ROWS I N BLOCK
SUB AH, BL
# ROWS TO BE MOVED
N2: ROW_LOOP
CALL NlO MOVE ONE ROW
ADD SI,BP
ADD 01, BP POINT TO NEXT LINE IN BLOCK
DEC AH
COUNT OF LINES TO MOVE
JNZ N2 ROW_LOOP
N3:
CLEAILENTRY
POP AX RECOVER ATTRIBUTE
IN AH
MOV AL, '
,
FILL WITH BLANKS
N4: CLEAILLOOP
CALL Nll CLEAR THE ROW
ADD 01, BP POINT TO NEXT LINE
DEC BL
COUNTER OF LINES TO SCROLL
JNZ N4 CLEAR_LOOP
N5 :
SCROLLEND
CALL DDS
CMP CRLMODE,7 IS THIS THE MONO CARD
JE N6 IF SO, SKIP THE MODE RESET
MOV AL,CRLMODE_SET GET VALUE OF THE MODE SET
MOV OX ,03D8H ALWAYS SET CGA CARD PORT
OUT
DX,AL
N6: VIDEO_RELHERE
2-92 ROM BIOS