Radio Shack CCR-81 Operation Manual

Computer Graphics Operation Manual
-----------TRS·BO ® ----------
;------------------------------------------------------------------
Print graphics screen to graphics printer
~~l
~~2
~~3
~~4
~~5
~~6
~~7
~~8
~~9
~l~
~ll
~12
~13
~14
~15
~16
~17
~18
~19
~2~
~21
~22
~23
~24
~25
~26
~27
~28
~29
~3~
~31
~32
~33
~34
~35
~36
~37
~38
~39
~4~
~41
~42
~43
~44
~45
~46
~47
~48
~49
GPRINT
PSECT
GPRINT
PUSH
PUSH
PUSH
PUSH
CALL
OR
OUT
CALL
XOR
OUT
LD
LD
LD
LD
LD
CALL
.
,
LOOPI LD
LD
LD
DEC
OUT
COLUMN LD
IN
AND
CALL
LD
PUSH
LD
INC
DECJ
DEC
JR
RLC
JR
PAST POP
OR
LD
INC
DJNZ
LD
INC
CP
CALL
~F~~~H
HL
DE
BC
IX
INITG
~DBH
(STATUS) ,A
INITBF
A
(X) ,A
(BPOS) ,A i
(XLOC) ,A i
HL,BGMODE
B,l
C,~DH
PRLINE
IX,BUFFER
B,24~
A,B
A
(Y) ,A
HL,MASK
A, (GRAPH)
(HL)
PO,SET~
HL,BPOS
BC
B, (HL)
B
B
Z,PAST
A
DECJ
BC
(IX)
(IX)
,A
IX
COLUMN
A,7
(HL)
(HL)
Z,PRNDRS
i
iSave registers
iOutput a Control byte to cause
i y to automatically dec. on a read
iSet A to ~
iInitialize the X position
" "bit position
" "" location counter
iBegin graphics print mode
ipoint IX at the printer buffer
igo through a whole column of bytes
iPut value in A and decrement
i so it can be put out as
i the Y position
ipoint HL at the mask byte
iinput a graphics byte
ichop off all but proper bit
iif result is odd parity set bit ~
i otherwise bit A is ~
ipoint HL at the bit position
isave register B (for DJNZ loop)
iget count
iincrement (in case it is ~)
imove bit left BPOS number of times
iif done, move on ...
imove bit left one position
irepeat loop
iget loop counter back
imerge A with byte of printer buffer
iput merged result in buffer
iincrement buffer pointer
icontinue loop
iSee if BPOS has gotten to 8.
i If it has (printer uses 7 bits)
print the buffer and reset
BPOS to ~
---------lIadlolhaeli---------
-79-

Radio Shack CCR-81 Specifications

General

Brand	Radio Shack
Model	CCR-81
Category	Desktop
Language	English