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SECOND LEVEL BOOTSTRAP
;
T H I S
LOADER I S
;
LOADER.
;
I T
CHECKSUMS I T S E L F ,
;
HAS BEEN LOADED CORRECTLY,
; RELOCATES THE MA^N PAPERTAPE LOADER.
;
NOTE THAT T H I S
; V ER S IO N OF THE MAIN PAPER TAPE LOADER.
0 0 0 0
ORG
0 0 2 0
3E13
B OO T2:
MV I
0 0 2 2
D 30 2
OUT
0 0 24 06 F 7
MV I
0 0 2 6
2 1 2 0 0 0
LX I
0 0 2 9 AF
XRA
;
PERFORM AN END-AROUND CHECKSUM,
; WE WE RE LOADED CORRECTLY
:
ADC
0 02A SE
c h e c k
I NX
0 0 2B 23
0 0 2C 05
DCR
0 0 2D C22AOO
JNZ
0 030 CEO O
AC I
0 0 3 2 BE
CMP
x x x :
JNZ
0 033 C 2 3 3 0 0
* » ;
•
;
WE DO THE FOLLOWING NONSENSE BECAUSE THE
;
BA SI C
KEY- IN BOOTSTRAP W ILL NOT LOAD
;
AN OFFH CHARACTER.
0 0 3 6
21BC 00
LX I
34
0 039
00 3A
2 IB I 0 0
LX I
0 03D 34
00 3E 2 1 0 B 0 1
LX I
0 0 4 1
34
; NOW WE'RE READY TO LOAD AND RELOCATE THE LOADER
/
0 0 4 2
C 3 5 E 0 0
JMP
3EAA
START:
MV I
0 0 4 5
OUT
0 0 4 7
D 3 0 3
3E 40
MV I
0 0 4 9
0 048 D 30 3
OUT
00 4D 3EFA
MV I
O0 4F D 3 0 3
OUT
3E1 7
MV I
0 0 5 1
D 30 3
OUT
0 0 5 3
DBO 3
:
0 0 5 5
s l
E 6 0 2
0 0 5 7
AN I
C A 5 5 0 0
0 0 5 9
005C DB02
STR:
0 0 5E DBO 3
E 601
0 0 6 0
AN I
0 0 6 2
C A5E00
JZ
MV I
0 0 6 5
3 E 1 1
0 3 0 2
0 0 6 7
OUT
PULLED
I N
BY THE B ASI C K E Y - I N
WHEN STARTED UP BY THE K E Y - I N LOADER,
TO MAKE SURE THAT I T
THEN PULLS I N AND
LOADER I S A S L IG H T L Y M O D IF IE D
2 OH
A , 1 3H
; GET STOP CHAR
2
; STOP THE READER
B,CHKSM- BOOT2 ; GET S IZ E OF LDR
H,BOOT2
; GET ADDRESS OF LDR
A
; CLEAR A AND CARRY
M
;ADD IN A BYTE W IT H CARRY
H
; BUMP POINTER
; DECREMENT COUNT
3
CHECK
; KEEP GOING
; ADD IN LAST CARRY
0
M
; COMPARE W IT H CHECKSUM
XXX
; HANG UP I F
H , F F 1 + 1
; GET ADDRESS OF ' I N
I NR
M
; MAKE I T
; DO I T A GAIN
H , F F 2 + 1
I NR
M
; AND AGAIN
H , FF 3+1
I NR
M
STR
; 1 S T T I M E ,
A,OAAH
; GET DUMMY MODE BYTE
3
A , 40H
; GET RESET COMMAND
3
; ISSUE
A , OFAH
; ISSUE MODE BYTE TO S IO
3
; ISSUE COMMAND BYTE
3
IN
03
; GET STATUS
; CHECK FOR CHAR READY
02
JZ
SL
; KEEP W A IT IN G
IN
02
; READ CHAR AND IGNOR
I N
; GET STATUS
03
1
;MAKE SURE WE HAVE XMTR RDY
STR
; GET ' X O N '
A , 11H
02
.•START READER
TO MAKE SURE
NO GOOD.
OFEH1 INS
' I N OFFH' .
S K IP R E - I N I T
STUFF
I T
CHAR
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