Radio Shack TRS-80 Operation Manual page 117

Computer Graphics
Operation Manual
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GPRT3 -- Print graphics X horizontal double Y axis
PSECT
~F.0JrHJ'H
PUSH HL
PUSH DE
PUSH BC
PUSH IX
CALL INITG
LD HL,BGMODE
LD B,l
LD C,.0DH
CALL PRLINE
LD
c,.0
LD A,.0E3H
OUT (STATUS),A
LD D,3
GPRT3
i
NEWLN
.
,
NEWRW
NEWRl
i
BYTE
PUSH
PUSH
LD
LD
LD
LD
LD
LDIR
POP
POP
LD
OUT
LD
CP
JR
INC
LD
XOR
OUT
LD
LD
CP
JR
LD
PUSH
IN
LD
LD
BC
DE
HL,BUF
DE, BUF+l
BC,639
A,
8~H
(HL)
,A
DE
BC
A,C
(Y) ,A
A,
4~H
D
Z,NEWRl
C
HL,BUF
A
(X) ,A
B,8~
A,4
D
NZ,BYTE
D,6
BC
A, (GRAPH)
C,A
E,8~H
iTurn on graphics print
iGraphics Y address
iBit(s) in buf to set
iClear buffer
iUpdate Y address
iIf printing row second time
iMove to next row
iRestart X address
iGet
8~
graphics bytes
iSave Y & loop counter
iSave graphics byte in C
iGet bits left to right
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