Imsai 8080 - Game Program Listing

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General Assembly a
Test Instructions
GAME PROGRAM LISTING
OCTAL HEX
ADD.
INST.
ADD. INST.
MNEMONIC
DESCRIPTION
000 000 257
0000 AF
X R A ,
Exclusive O R A to itself (put zero in A)
001
147
01 67
MOV H, A
Move A to H (put zero in H)
002
333 02
DB
INP
Input data
003 377
03
FF
from front panel switches
004
157
04
6F MOV L, A
Move A to L
005
371
05
F9
SPHL
Put H & L reg. into SP
008
257
06 AF
XRA, A
Exclusive OR A to itself (put zero in A)
007
201
07 81
ADD C
Put C in A, affecting flag bits
010
302
08
C2
JNZ
Jump if not zero
011
023
09
13
(skip switch test for debounce after a switch change)
012
000
0A 00
IF N O R M A L , C O NTINU E
013
123
0B 53
MOV D„ E
Move E to D
014 333 OC
DB INP
Input data
015 377
OD FF
from front panel switches
016 137
OE 5F
MOV E, A
Move A to E
017
252
OF
AA XRA, D
Exclusive OR D to A
020 302 10
C2 JNZ
Jump if result not all O's
021
041 11
21
(change display if switch position changed from last time)
022
000
12
00
IF SW ITCHES U N C H A N G E D, C O NTIN U E
023 071 13 39 DAD SP
Add SP to HL
024 322
14
D2 JNC
Jump if no carry results
025
006
-15
06
(return to read switch loop if no carry yet)
026
000
16
00
IF C A R R Y , C O N TIN U E
027 170 17 78 MOV A, B
Move 8 to A
030
007
18
07
RLC
Rotate left 1
031 107 19
47 MOV B, A
Store A in 8
032
323
1A
D3
OUT
Output A
033 377 IB
FF
in front panel lights
034 257 1C AF
XRA, A
Exclusive OR A to itself (put zero in A)
035
117
ID
4F MOV C, A
Move A to C (Reset debounce indicator)
© 1975 IMS Assoc IN