IBM PC CONVERTIBLE Technical Reference page 120

0308
03DA
03DC
0300
03EO
03EO
03EO
03E2
03E4
03E6
03E8
03EC
03EE
03FO
03FO
03F4
03F6
03F6
03F9
03FB
03FC
03FC
03FC
03FF
0401
0404
0406
0409
0409
040B
040C
0400
0410
0412
0413
0414
0414
0418
041B
041C
041C
0410
041F
0421
0422
0422
0423
0425
0427
0429
042A
A8 01 TEST AL, HORLRETRACE IS IT HIGH
74 FB JZ P3 WAIT UNTIL IT IS
AD LODSW GET THE CHAR/ATTR
E9 016F R JMP
VIDEO_RETURN
READ....ACCURRENT ENDP
FIND_POSITION
PROC NEAR
8A CF MOV CL, BH DISPLAY PAGE TO CX
32 ED XOR CH, CH
8B F1 MOV SI,CX MOVE TO SI FOR INDEX
01 E6 SAL SI,I
; *
2 FOR WORD OFFSET
8B 84 0050 R MOV AX, [SI+ OFFSET CURSOR_POSN- ; GET ROW/COL OF PAGE
33 DB XOR BX, BX SET START ADDRESS TO ZERO
E3 06 JCXZ P5
NO_PAGE
P4:
PAGE_LOOP
03 1E 004C R ADD BX,CRLLEN LENGTH OF BUFFER
E2 FA LOOP P4
P5:
NO_PAGE
E8 02E6 CALL POSITION DETERMINE LOCATION IN REGEN
03 08 ADD BX ,AX ADD TO START OF REGEN
C3 RET
FI ND_POS IT ION
ENDP
WRITE....ACCURRENT
80 FC 04
72 08
80 FC 07
74 03
E9 05BD R
8A E3
50
51
E8 03EO R
8B FB
59
5B
INPUT
OUTPUT
THIS ROUTINE WRITES THE ATTRIBUTE
AND CHARACTER AT THE CURRENT CURSOR
POSITION
(AL)
=
CHAR TO WRITE
(BH)
=
DISPLAY PAGE
(BL)
=
ATTRIBUTE OF CHAR TO WRITE
(CX)
=
COUNT OF CHARACTERS TO WRITE
(AH)
=
CURRENT CRT MODE
(OS) DATA SEGMENT
(ES) REGEN SEGMENT
NONE
INTERRUPTS: DISABLED DURING THE WRITE
WRlTE....ACCURRENT
PROC NEAR
CMP
AH,4 IS TH I S GRAPH I CS
JC P6
CMP AH,7
IS THIS MONO CARD
JE
P6
JMP GRAPHICS_WRITE
P6: WRITE....ACCONTINUE
MOV AH, BL GET ATTRI BUTE TO AH
PUSH AX SAVE CHAR/ATTRIBUTE
PUSH CX SAVE WRITE COUNT
CALL FIND_POSITION
MOV 01, BX ADDRESS TO 01 REGISTER
POP CX WRITE COUNT
POP BX CHARACTER/ A TTR IN BX REG
P7 : WRITE_LOOP
;----- WAIT FOR HORIZONTAL RETRACE
8B 16 0063 R MOV OX ,ADDR_6845 GET BASE ADDRESS
83 C2 06 ADD DX,6 POINT AT STATUS PORT
9C PUSHF SAVE CURRENT FLAGS
P8:
EC IN AL,DX GET STATUS
A8 01 TEST AL, HORLRETRACE IS IT LOW
75 FB JNZ P8 WAIT UNTIL IT IS
FA CLI NO MORE INTERRUPTS
P9:
EC IN AL,DX GET STATUS
A8 01 TEST AL, HORLRETRACE IS IT HIGH
74 FB JZ P9 WAIT UNTIL IT IS
8B C3 MOV AX,BX RECOVER THE CHAR/ATTR
AB STOSW PUT TH E CHAR/ A TTR
90 POPF INTERRUPTS BACK ON - I F
em
ROM BIOS 2-95