IBM XT 5160 - Page 216

WA I T FOR HOR I ZONTAL RETRACE OR VERTI CAL RETRACE I F COLOR 80
PAGE
;----- IF AMOUNT OF LINES TO BE SCROLLED: AMOUNT OF LINES IN WINDOW
THEN
ADJUST AL; ELSE RETURN;
TEST _L I NE_COUNT PROC NEAR
:- ~~~~ - ~~ - ~~~~~~~ ------------------------------------------------------------- --
; - TH I S ROUT I NE READS THE ATTR I BUTE AND CHARACTER AT THE CURRENT
; CURSOR POS I T I
ON AND RETURNS THEM TO THE CALLER
INPUT
( AH) : CURRENT CRT MODE
; (BH) : DISPLAY PAGE ( ALPHA MODES ONLY)
(OS) : DATA SEGMENT
( ES) : REGEN SEGMENT
; OUTPUT
(
AL ) : CHARACTER READ
(AH) : ATTRIBUTE READ
; ------- ~~~~~~- -~~~~~ ~~: ~~~~~ ~~ ----------------------------------------------- --
5-69
ELSE SET BUFFER START ADDRESS TO ZERO
ADD
LENGTH OF BUFFER FOR ONE PAGE
DECREMENT PAGE COUNT
LOOP
TILL PAGE COUNT EXHAUSTED
DETERMINE LOCATION IN REGEN IN PAGE
GET
COLUMNS PER ROW COUNT
DETERM I NE BYTES TO ROW
ADD I N COLUMN VALUE
• 2 FOR ATTR I BUTE BYTES
ADD LOCATION TO START OF REGEN PAGE
GET
BASE ADDRESS OF ACTIVE DISPLAY
OX: STATUS PORT ADDRESS· OF ADAPTER
BP: ATTR I BUTE / CHARACTER (FROM BL / AL)
01: POS I T I ON (OFFSET I N REGEN BUFFER)
BL: MODE FLAG (ZERO FOR 80X25 COLOR)
;
IS THIS GRAPHICS
; I S TH I S BW CARD
SAVE
LI NE COUNT IN BL
TEST IF AL I S ALREADY ZERO
I
FIT I S THEN RETURN •••
SAVE AX
SUBTRACT LOWER ROW FROM UPPER ROW
ADJUST 0 I FFERENCE BY 1
LINE COUNT : AMOUNT OF ROWS IN WINDOW?
RESTORE AX
I F NOT THEN
WE'RE ALL SET
OTHERW I SE SET BL TO ZERO
; RETURN
; READ
AC CONT I NUE
;
GET REGEN LOCATION AND PORT ADDRESS
;
ESTABLISH ADDRESSING IN SI
; GET REGEN SEGMENT FOR QU I CK ACCESS
1-8
01-10-86
VIDEO (01/10/86)
NEAR
NEAR
BL,AL
AL,AL
BL SET
AX-
AL,DH
AL,CH
AL
AL,BL
AX
BL SET
BL-;"BL
01,01
PROC
AH,BL
BP,AX
BL,2
BL,I
AL,BH
SETUP FOR BUFFER READ OR WR I TE
SWAP MODE TYPE WITH A TTR I BUTE
SAVE CHARACTER/ATTR IN (BP) REGISTER
CONVERT 0 I SPLA Y MODE TYPE TO A
ZERO
VALUE FOR COLOR IN 80 COLUMN
MOVE
01 SPLAY PAGE TO LOW BYTE
; CLEAR HIGH BYTE FOR BYTE OFFSET
01 ,AX ; MOVE 0 I SPLA Y PAGE (COUNT) TO WORK REG
01, I ; TIMES 2 FOR WORD OFFSET
DX,[DI+OFFSET OCURSOR POSN) ; GET ROW/COLUMN OF THAT PAGE
P21 - SK I P BUFFER ADJUSTMENT I F PAGE ZERO
MOV
OR
JZ
PUSH
MOV
SUB
INC
CMP
POP
JNE
SUB
ADD 0 I
,OCRT LEN
DEC AX -
JNZ P20
RET
TEST _LI NE_COUNT ENDP
OR
BL,BL
CHECK MODE FLAG FOR COLOR CARD IN 80
JNZ
P13
ELSE SKIP RETRACE WAIT - DO FAST READ
Pll :
WA I T FOR HORZ RETRACE LOW OR VERT I CAL
STI
ENABLE INTERRUPTS FIRST
NOP
ALLOW FOR
SMALL INTERRUPT WINDOW
CLI
BLOCK
I
NTERRUPTS FOR SINGLE LOOP
IN
AL,DX
GET STATUS FROM THE ADAPTER
TEST
AL,RHRZ
IS HOR I ZONT AL RETRACE LOW
JNZ
Pll
WA I T UNT I LIT I S
P12:
NOW WA I T FOR EITHER RETRACE HIGH
IN
AL,DX
GET STATUS
TEST
AL,RVRT+RHRZ
I S HOR I ZONT AL OR VERT I CAL RETRACE HIGH
JZ
P12
WAIT UNTIL EITHER IS ACTIVE
P13:
LODSW
GET THE CHARACTER AND ATTR I BUTE
JMP
V IDEO_RETURN
EXIT WITH
(AX)
READ_ AC _CURRENT ENDP
CMP
AH,1
JE
Pl0
JMP
GRAPH I CS_READ
Pl0:
CALL
FIND POSITION
MOV
SI,DT
PUSH
ES
POP
OS
READ AC CURRENT PROC
-
-CMP AH,4
JC Pl0
FIND POSITION
- XCHG
MOV
SUB
SHR
MOV
CBW
MOV
SAL
MOV
JZ
XOR
P21:
P20:
MOV AL, BYTE PTR OCRT COLS
MUL DH -
XOR DH,DH
ADD AX,OX
SAL AX,I
ADD OI,AX
MOV OX, OADDR 6845
ADD OX,6 -
RET
F I NO _POS I TI ON ENDP
IBM Personal Computer MACRO Assembler Version 2.00
VIOEO ---- 01/10/86 VIDEO DISPLAY BIOS
191
198
199
800
801 02EA
802
803
02EA 8A 08
804 02EC OA CO
805 02EE 14 OE
806 02FO 50
801 02F 1 8A C6
808 02F3 2A C5
809 02F5 FE CO
810 02F1 3A C3
81 I 02F9 58
812 02FA 15 02
813 02FC 2A DB
814 02FE
815 02FE C3
816 02FF
811
818
819
820
821
822
823
824
825
826
821
828
829
830
831
832
833
02FF
834 02FF 80 FC 04
835 0302 12 08
836
831 0304 80 FC 01
838 0301 14 03
839
840 0309 E9 063E R
841 030C
842 030C E8 0328 R
843 030F 8B F1
844 0311 06
845 0312 1F
846
841
848
849
03 I 3 OA DB
850 0315 15 00
851 0311
852 0311 FB
853 0318 90
854 0319 FA
855 031 A EC
856 031 B A8 0 I
851 0310 15 F8
858 031 F
859 031F EC
860 0320 A8 09
861 0322 14 FB
862 0324
863 0324 AD
864 0325 E9 0130 R
865
866 0328
861
868
869
810 0328
811 0328 86 E3
812 032A 8B E8
813 032C 80 EB 02
814 032F DO EB
815 0331 8A C1
816 0333 98
811 0334 8B F8
818 0336 01 E1
819 0338 8B 95 0050 R
880 033C 14 09
881
882 033E 33 FF
883 0340
884 0340 03 3E 004C R
885 0344 48
886 0345 15 F9
881
888
0341
889 0341 AO 004A R
890 034A F6 E6
89 I 034C 32 F6
892 034E 03 C2
893 0350 OlEO
894 0352 03 F8
895 0354 8B 16 0063 R
896 0358 83 C2 06
891 035B C3
898
899
035C