Radio Shack TRS-80 Operation Manual page 110

Operation Manual
Computer Graphics
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SET~
LD A,l ;set A to binary
~~~~ ~~~l
RET ; and return
.
,
INITBF LD
LD
LD
LD
LD
LDIR
RET
;End graphics print mode
;Restore registers
;Initialize the printer buffer
with all
8~H
;Print a line. HL==>line to print
;B =
# characters to print
;C = EOL char (sent after line)
;HL, BC, AF, and DE used
;Set up the
; PRLINE call and
send the buffer
;clear A
;reset bit position counter
;otherwise increment the X counter
;and store it back
;also update the port value
;now go get another row of bits
;After getting a vertical row of bits
; rotate the mask right one position
;Check to see if its back to
; it's original value, if not
; go get another row of bits
;If so, get X pos (to increment it)
;Check to see if we are at the end •••
$
A,
(HL)
HL
3BH
PRLINE
A,C
3BH
HL,BUFFER
DE,BUFFER+l
BC,239
A,8~H
(HL)
,A
HL,BUFFER
B,24~
C,~DH
PRLINE
A
(BPOS) ,A
PRNDRS
HL,EGMODE
B,l
C,~DH
PRLINE
IX
BC
DE
HL,MASK
(HL)
A,
8~H
(HL)
NZ,LOOPl
A, (XLOC)
79
Z,BYE
A
(XLOC) ,A
(X) ,A
LOOPl
LD
LD
LD
CALL
XOR
LD
CALL
LD
LD
LD
CALL
POP
POP
POP
LD
RRC
LD
CP
JR
LD
CP
JP
INC
LD
OUT
JR
BYE
PRLINE EQU
LD
INC
CALL
DJNZ
LD
CALL
RET
PRNDRS
~5~
~5l
~52
~53
~54
~55
~56
~57
~58
~59
~6~
~6l
~62
~63
~64
~65
~66
~67
~68
~69
~7~
~7l
~72
~73
~74
~75
~76
~77
~78
~79
~8~
~8l
~82
~83
~84
~85
~86
~87
~88
~89
~9~
~9l
~92
~93
~94
~95
~96
~97
~98
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