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APPENDIX B
The display would appear similar to this:
Once a subroutine is written in a given location, care
must be exercised that it is not accidentally changed.
For example, storing a trace in trace C would destroy
the subroutine beginning at DA 3080.
LOOP INSTRUCTIONS
Load Counter Register (Idc) and Decrement and Skip on Zero (dsz).
looping is used to draw a grid in two places on the CRT display on refresh. The trace C page is programmed to
contain the graphics.
address
3072
3073
3074
3075
3076
positioning
vector
3077
3078
3079
3080
3081
3082
3199
3200
3201
3202
3203
3204
looping
3205
3206
subroutine
3207
3208
3209
3210
3211
3212
3213
description
plot absolute
x = 600 (PA)
y = 300 (PU)
jump to subroutine
at address
plot absolute
x = 100 (PA)
y = 300 (PU)
jump to subroutine
at address
end of display
vector
repeat 10 times
plot relative
x = 0 (PR)
y = +25(PU)
x = + 300 (PR)
= 0
y
(PD)
x = 0 (PR)
x = -3OO(PR)
y = 0 (PD)
decrement
jump to
start
return
ADVANCED DISPLAY PROGRAMMING
In the following example,
program
600
300 + 2048
jsb
address
100
300 + 2048
jsb
address
end
Idc + 10
vtr
25 + 2048
300 + 2048
0
1024-300 + 2048
0
address
rtn
word
1026
600
2348
1163
3199
1026
100
1163
3199
1028
1026
1546
1026
2048
2073
2348
0
2048
2073
2772
0
1099
1035
3201
1227
Appendix
2 1
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