Radio Shack TRS-80 Operation Manual page 119

Computer Graphics
TRS-BO@
Operation Manual
,.....---..
~fiffif98
ADD HL,DE
~fiffif99
XOR A
~fif1fif~
CP
(HL)
iEnd of buffer?
~fif1~l
JR
Z,EPRT
~fif1fif2
LD C, (CTL)
~fif1fif3
CALL PRLINE
~fif1fi14
LD HL,2l4
fi1fi11fi1S
ADD HL,DE
iNext part of buffer
fi1fi1lfi16
EX DE,HL
~fif1fi17
JR PART
fi1fi1lfi18
EPRT
POP BC
fi1fif1fi19
RET
fi1fif1lfi1
·
,
~fi111l
PRLINE EQU
$ iPrint a line. HL==>line to print
fi1fif1l2
PUSH DE
fi1fi1l13 PRL2 LD A, (HL)
iB
=
# characters to print
~fi1114
INC HL
iC
=
EOL char (sent after line)
~fi1l1S
CALL 3BH
iHL, BC, AF, and DE used
fi1fif1l6 DJNZ PRL2
~fifl17
LD
A,C
~fifl18
OR
A
~fi1119
CALL NZ,3BH
fi1fif12fi1
POP DE
fi1fifl2l RET
~
~fif122
·
,
fi1fi1l23 i INITG -- Initialize Model III Graphics Board
fi1
fif12 4
·
,
~fifl2S
INITG
LD A, lfi1H
fi1fi1126
OUT
(236),A
iTurn on port
fi1fifl27 LD BC,lS
~fif128
LD HL,DATA
fi1fi1l29 LOOP
LD A,B iProgram CRTC chip for
8fi1
by 24
~fif13fi1
OUT (136) ,A
~fifl31
LD
A, (HL)
fi1fif132
OUT <l37),A
~fifl33
INC HL
~fif134
INC
B
~fifl3S
LD A,B
~fif136
CP
C
fi1fi1l37 JR NZ,LOOP
~fif138
RET
~fif139
DATA DEFB
99
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