Radio Shack TRS-80 Operation Manual page 113

Computer Graphics
Operation Manual
TRS-BO®
i~
~l1l1fn
GPRT2 -- Print graphics X horizontal
~1111112
~1111113
PSECT
~F~l1l1H
111111114 GPRT2 PUSH
HL
111111115 PUSH DE
~1111116
PUSH BC
~1111117
PUSH
IX
111111118
CALL INITG
111111119
LD
HL,BGMODE iTurn on graphics print mode
~1111111
LD B,l
11111111 LD C,,0DH
11111112 CALL PRLINE
~111113
LD c,,0 iGraphics Y address
11111114 LD A,,0E3H
11111115 OUT (STATUS) ,A
11111116
.
,
~111117
NEWLN PUSH BC
11111118
LD HL,BUF
iClear buffer
11111119 LD DE, BUF+l
11~11211
LD BC,639
11111121
LD A,811H
~111122 LD (HL) ,A
11111123
LDIR
"~,
11111124 i
~111125 POP
BC
11~1126
LD D,l iBit in buf to set
11111127 i
~111128
NEWRW LD A,C
11111129
OUT (Y) ,A iUpdate Y address
111111311
INC C
11111131
LD HL,BUF
~111132 XOR A
~111133
OUT
(X) ,A
iRestart X address
11111134
LD B,811 iGet 811 graphics bytes
11111135
.
,
11111136 BYTE PUSH
BC
iSave Y & loop counter
11111137
IN A, (GRAPH)
~111138 LD C,A iSave graphics byte in C
~111139
LD E,811H iGet bits left to right
1111114~ BIT
LD A,C
11111141
AND E
11111142
JR Z,OFFI
11111143
LD A,D
~111144 OR
(HL)
11111145
LD (HL) ,A iSet bit in buffer
11111146 OFFI INC HL iNext buffer byte
11111147
SRL E
iNext bit
----------Itadlelllaeli - - - - - - - - -
-83-