Page 7 - Enterpress Magazine - 2017/5-6.

2017/5-6. September–December page 7

NEMHIBA1 CALL LPT RRA
LD A,(VIDS) RRA
OUT (0B1H),A AND 3
LD A,(P2S) OR 18H
OUT (0B2H),A OR (IX+1)
XOR A LD (HL),A
LD DE,(VIDCIM2) INC HL
LD HL,VIDCIM2+1 LD (HL),E
RRD INC HL
RLCA LD (HL),D
RLCA ADD HL,BC
RLCA INC D
RLCA LD A,D
LD (LPTL),A AND 7
OUT (82H),A JR NZ,L2
OR 0C0H LD A,E
RRD ADD A,32
LD (LPTH),A LD E,A
OUT (83H),A CCF
LD (VIDCIM2),DE SBC A,A
AND 0F8H
Creating a LPT, which I mentioned below, changes com- ADD A,D
pared to the original procedure because it is not at a fi- LD D,A
xed location, so you need to handle the changing video L2 EX AF,AF’
addresses. DEC A
JR NZ,L1
LPT: LD DE,(VIDCIM2) EXX
LD HL,0 LD HL,SYNC
RRA LD BC,HOSSZ
RR H LDIR
RRA RET
RR H LINE DB 255,14H,15,2FH,0,0,0,0
ADD HL,DE TABL DB 0,36,121,88,130,182,219,63
LD (VIDCIM2),HL SYNC DB 0F5H,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0
LPT2: LD A,(LPTS) STATUS DB 247,8,11,73H,0B8H,
OUT (0B1H),A 0FEH,0E9H, 1,0,216, 216,0,0,0,0,0
LD A,192 DB 217,12H,63,0,0,0,0,0,0,0,0,0,0,0,0,0
LD DE,(VIDCIM2) DB 253,16,63,0,0,0,0,0,0,0,0,0,0,0,0,0
RES 7,D DB 252,16,6,63,0,0,0,0,0,0,0,0,0,0,0,0
SET 6,D DB 255,90H,63,32,0,0,0,0,0,0,0,0,0,0,0,0
EXX DB 252,12H,6,63,0,0,0,0,0,0,0,0,0,0,0,0
LD DE,(VIDCIM1) DB 207,13H,63,0,0,0,0,0,0,0,0,0,0,0,0,0
LD IX,VIDCIM1 HOSSZ EQU $-SYNC
LD HL,(VIDCIM2)
RES 7,H The end
SET 6,H
INC HL
INC HL
INC HL
INC HL
LD BC,13
L1 EX AF,AF’
EXX
LD HL,LINE
LD BC,16
LDIR
EXX
LD (HL),E
INC HL
LD A,D
RRA