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DEC PDP-11 Boot Monitor
BOOTMON.mac is a custom boot monitor/loader based on boot.mac written by Paul Nankervis.
BOOTMON.mac was cross-assembled with MACRO11 to produce BOOTMON.txt, which was then processed by FileDump to produce BOOTMON.json, which is preloaded in a number of our PDP-11 test machines. To see it in action, try the PDP-11/70 Boot Monitor with Debugger.
The BOOTMON.mac source code is shown below.
; BOOT MONITOR
;
; REBASE HIGHER LINK/BOT:140000
; WANT PERFORMANCE COUNTER - CLOCK TICKS TO DO SOMETHING?
KW11LKS = 177546
KW11VEC = 100
DL11RCSR = 177560
DL11RBUF = 177562
DL11XCSR = 177564
DL11XBUF = 177566
DL11VEC = 64
PSW = 177776
.ASECT
.=140000
START: RESET
CLR @#PSW
MOV #START,SP
CLR @#DL11XCSR ; CLEAR THE XCSR
MOV #BANNER,R0
JSR PC,PRINT
MOV #CLKAST,@#KW11VEC
MOV #340,@#KW11VEC+2
BIS #100,@#KW11LKS ; SET CLOCK TICKING
MOV #PROMPT,R0
JSR PC,PRINT
SUB #256,SP
MOV SP,R0
JSR PC,INPUT
CLR R0
1$: WAIT
INC R0
TST LGHTON
BEQ 1$
MOV #054000,-(SP) ; SUPER PRIORITY 0 ALT REG
MOV LGHTON,-(SP) ; CALL SUPER LOOP START
RTI
LGHTON: .WORD 0
CLKTIC: .WORD 0
CLKAST:
INC CLKTIC
RTI
ONECHR:
TSTB @#DL11XCSR
BPL ONECHR
MOVB R0,@#DL11XBUF
RTS PC
PRTPTR: .WORD 0
PRINT:
BITB #100,@#DL11XCSR
BNE PRINT
MOV R0,PRTPTR
MOV #PRTAST,@#DL11VEC
MOV #200,@#DL11VEC+2
BISB #100,@#DL11XCSR
RTS PC
PRTAST:
TSTB @PRTPTR
BEQ 2$
MOVB @PRTPTR,@#DL11XBUF
INC PRTPTR
RTI
2$: CLRB @#DL11XCSR
RTI
BUFFER: .WORD 0 ; INPUT BUFFER POINTER
LENGTH: .WORD 0 ; INPUT BUFFER LENGTH
INPUT:
MOV R0,BUFFER
CLR LENGTH
MOV #INPAST,@#60
MOV #200,@#62
BISB #100,@#DL11RCSR
RTS PC
INPAST:
MOV R0,-(SP)
MOVB @#DL11RBUF,R0
BIC #340,@#PSW ; HACK TO PERMIT XBUF INTERRUPTS WHILE RBUF INTERRUPT HANDLER STILL RUNNING
CMPB R0,#15
BEQ 7$ ; CARRIAGE RETURN
CMPB R0,#127.
BEQ 2$ ; <DEL>
CMPB R0,#10
BNE 4$ ; BACK SPACE
2$: TST LENGTH ; DATA IN BUFFER?
BEQ 3$
DEC LENGTH ; LENGTH
MOV #DEL,R0
JSR PC,PRINT
3$: BR 9$
4$: CMPB R0,#40
BLT 9$ ; BELOW SPACE
CMPB R0,#177
BGE 9$ ; SKIP STUFF TOO BIG
JSR PC,ONECHR ; ECHO CHAR
CMPB R0,#172
BGT 5$ ; ABOVE Z
CMPB R0,#141
BLT 5$ ; BELOW A
BICB #40,R0 ; CONVERT TO UPPER CASE
5$: CMP LENGTH,#254
BGE 9$
MOVB R0,-(SP)
MOV BUFFER,R0
ADD LENGTH,R0
MOVB (SP)+,(R0)
INC LENGTH
BR 9$
7$: MOV BUFFER,R0
ADD LENGTH,R0
CLRB (R0)
MOV #CMD,@#240 ; CALL CMD AT PRIORITY 2
MOV #100,@#242
MOV #2000,@#177772
9$: MOV (SP)+,R0
RTI
CMD:
CLR @#177772 ; NO MORE PIR CALLS
MOV R0,-(SP)
MOV R1,-(SP)
MOV R2,-(SP)
MOV R3,-(SP)
MOV R4,-(SP)
MOV #EOL,R0
JSR PC,PRINT
1$: BITB #100,@#DL11XCSR
BNE 1$
CLR R4
MOV #CMDLST,R3 ; CMD LIST
3$: MOVB (R3)+,R0
BEQ 13$
MOV BUFFER,R2 ; USER CMD
4$: MOVB (R2)+,R1
BEQ 15$ ; NULL COMMAND?
CMPB R1,#40
BEQ 4$ ; SKIP SPACE
5$: CMPB R0,R1
BNE 7$
MOVB (R3)+,R0
BEQ 9$
MOVB (R2)+,R1
BEQ 9$
CMPB R1,#40
BNE 5$
BR 9$
7$: MOVB (R3)+,R0
BNE 7$
INC R4
BR 3$
9$: ASL R4
JSR PC,@CMDTBL(R4) ; EXECUTE
BR 15$
13$: MOV #UNKMSG,R0
JSR PC,PRINT
15$: CLR LENGTH
MOV #PROMPT,R0
JSR PC,PRINT
MOV (SP)+,R4
MOV (SP)+,R3
MOV (SP)+,R2
MOV (SP)+,R1
MOV (SP)+,R0
RTI
CMDTBL: .WORD BOOT,HALT,TEST,DIAG,LIGHTS,HELP
HLPMSG: .ASCIZ 'COMMANDS ARE BOOT, HALT, TEST, DIAG, LIGHTS AND HELP'<15><12>'BOOT DEVICES ARE RK? RL? OR RP?'<15><12>
EOL: .BYTE 15,12,0
DEL: .BYTE 10,40,10,0
CMDLST: .ASCIZ 'BOOT'
.ASCIZ 'HALT'
.ASCIZ 'TEST'
.ASCIZ 'DIAG'
.ASCIZ 'LIGHTS'
.ASCIZ 'HELP'
.BYTE 0
UNKMSG: .ASCIZ 'UNKNOWN COMMAND'<12><15>
BANNER: .ASCIZ 'PDP-11 MONITOR V1.0'<12><15><12><15>
; 'ADAPTED FROM CODE BY PAUL NANKERVIS <PAULNANK@HOTMAIL.COM>'<12><15><12><15>
PROMPT: .ASCIZ 'BOOT> '
BADBOO: .ASCIZ 'UNKNOWN BOOT DEVICE'<12><15>
PERMSG: .ASCIZ ' CLOCK TICKS'<12><15>
LOOMSG: .ASCIZ ' ITERATIONS'<12><15>
.EVEN
HELP:
MOV #HLPMSG,R0
JSR PC,PRINT
RTS PC
HALT:
HALT
MOV #EOL,R0
JSR PC,PRINT
RTS PC
TEST:
CLR CLKTIC
MOV #15000,R5
10$: MOV R5,@#177570 ; DISPLAY
MOV R5,R4
ASR R4
15$: CLR R0
MOV R5,R1
DIV R4,R0
MOV R0,R2
MUL R4,R2
ADD R3,R1
CMP R1,R5
BEQ 20$
HALT
20$: SOB R4,15$
SOB R5,10$
MOV #PERMSG+5,R0
MOV CLKTIC,R3
25$: CLR R2
DIV #10,R2
ADD #'0,R3
MOVB R3,-(R0)
MOV R2,R3
BNE 25$
JSR PC,PRINT
RTS PC
LOOCNT: .WORD 0
DIAG:
CLR LOOCNT
CLR CLKTIC
DIAGLP:
CLR R5
BMI L1
BVS L1
BHI L1
BLT L1
BLOS L2
L1: HALT
L2: DEC R5
BPL L3
BEQ L3
BGE L3
BLE L4
L3: HALT
L4: ROR R5
BVC L5
BCC L5
BNE L6
L5: HALT
L6: MOVB #17,@#177776
BPL L7
BVC L7
BLT L7
BHI L7
BMI L8
L7: HALT
L8: MOV #77777,R3
ADD #77777,R3
CMPB @#177776,#5
BNE L9
HALT
L9: MOVB #1700,R4
BPL L10
CMP R4,#177700
BEQ L11
L10: HALT
L11: CLRB R4
CMP R4,#177400
BEQ L12
HALT
L12: MOV #125252,R5
MOV R5,R0
MOV R0,R1
MOV R1,R2
MOV R2,R3
MOV R3,R4
MOV R4,R5
SUB R5,R1
BLT NODIAG
BEQ L13
NODIAG: HALT
L13: ROL R2
BCC L14
BLT L15
L14: HALT
L15: ADD R2,R3
INC R3
COM R3
ADD R3,R1
BCS L16
BLE L17
L16: HALT
L17: ROR R4
BIS R4,R3
ADD R5,R3
INC R3
BCS L18
DEC R1
BLT L19
L18: HALT
L19: COM R0
BLOS L20
HALT
L20: BIC R0,R1
ADD R1,R1
BGT L21
BLE L22
L21: HALT
L22: SWAB R1
CMP R1,#052125
BNE L23
BIT R4,R5
BGT L23
COM R5
BNE L24
L23: HALT
L24: MOVB #177401,R0
BPL L26
L25: HALT
L26: SOB R0,L25
CLR R1
L27: INC R1
SOB R0,L27
TST R0
BNE L28
TST R1
BEQ L29
L28: HALT
L29: MOV #N1,PC
HALT
N1: TST (PC)+
HALT
N2: MOV #N3,-(SP)
RTS PC
HALT
N3: CLR -(SP)
MOV #N4,-(SP)
RTI
HALT
N4: JMP @#N5
HALT
N5: MOV #3,R5
CLR @#6
MOV #N6,@#4
TST -(R5)
HALT
N6: ADD #4,SP
CLR R0
MOV #7777,R1
N7: MOV R0,R2
ADD #5,R2
CMP (R0)+,-5(R2)
BEQ N8
HALT
D1: .WORD 0
N8: SOB R1,N7
INC LOOCNT
BCC 10$
HALT
10$: CMP CLKTIC,#2200
BHI 20$
JMP DIAGLP
20$: MOV #LOOMSG+5,R0
MOV LOOCNT,R3
25$: CLR R2
DIV #10,R2
ADD #'0,R3
MOVB R3,-(R0)
MOV R2,R3
BNE 25$
JSR PC,PRINT
RTS PC
MMR0=177572
MMR1=177574
MMR2=177576
MMR3=172516
LIGHTS:
MOV #77406,R3 ; DEFAULT PDR
CLR R2
CLR R1
MOV #8.,R0
1$: MOV R3,172300(R1) ; KERNEL I PDR
MOV R2,172340(R1) ; KERNEL I PAR
MOV R3,172320(R1) ; KERNEL D PDR
MOV R2,172360(R1) ; KERNEL D PAR
MOV R3,172200(R1) ; SUPER I PDR
MOV R2,172240(R1) ; SUPER I PAR
MOV R3,172220(R1) ; SUPER D PDR
MOV R2,172260(R1) ; SUPER D PAR
MOV R3,177600(R1) ; USER I PDR
MOV R2,177640(R1) ; USER I PAR
MOV R3,177620(R1) ; USER D PDR
MOV R3,177660(R1) ; USER D PAR
ADD #200,R2
ADD #2,R1
SOB R0,1$
BIS #176000,@#172376 ; KERNEL D POINTS TO I/O SPACE
BIS #176000,@#172276 ; SUPER D POINTS TO I/O SPACE
BIS #176000,@#177676 ; USER D POINTS TO I/O SPACE
MOV #77,@#MMR3 ; 77 FOR 22 BIT
MOV #1,@#MMR0
MOV #1700,@#172244 ; BASE SUPER I (PAR 2) #40000 AT #170000
MOV #1700,@#172264 ; BASE SUPER D (PAR 2) #40000 AT #170000
MOV #010000,@#177776 ; SET PM TO SUPER
MOV #40200,R3 ; SUPER CODE ADDRESS
MOV #SUPERS,R2 ; ADDRESS SUPER CODE
10$: MOV (R2)+,-(SP)
MTPI (R3)+
CMP R2,#SUPERE
BLO 10$
MOV #40200,LGHTON ; CHANGE IDLE TASK
RTS PC
;
; TO BE COPIED TO SUPER #40200 AT PHYSICAL #170000
; #40000 TO #40200 FOR WAIT & JMP INSTRUCTIONS
;
SUPERS:
MOV #37,R0 ; LOAD PATTERN
MOV #174000,R1
BIT #1,@#177570
BEQ 10$
MOV #7417,R0
MOV R0,R1
COM R1
BIT #2,@#177570
BEQ 10$
MOV #36163,R0
MOV #37000,R1
10$: MOV R1,R2
SUB #2,R2
BIC #1,R2 ; WAIT ADDRESS
MOV R2,R3
BIC #177701,R3 ; ADDRESS OFFSET
MOV #0000001,40000(R3) ; WRITE WAIT
ADD #2,R3
MOV #0000113,40000(R3) ; WRITE JMP (R3)
MOV R2,R4
ASH #-6,R4
BIC #177600,R4
MOV #1700,R5
SUB R4,R5 ; PAR ADDRESS BASE FOR WAIT
MOV R2,R4
ASH #-12.,R4
BIC #177761,R4 ; PAR SELECT OFFSET
MOV R5,172240(R4) ; SUPER I SPACE
MOV R1,R3
ASH #-12.,R3
BIC #177761,R3 ; PAR SELECT OFFSET
CMP R3,R4 ; SAME PAR
BEQ 30$
MOV R1,R4
ASH #-6,R4
BIC #177600,R4
MOV #1700,R5
SUB R4,R5 ; PAR ADDRESS BASE FOR JMP
MOV R5,172240(R3) ; SUPER I SPACE
30$:
MOV #3,R4
ADD @#177570,R4
MOV #2,R3
ADD PC,R3
40$: JMP (R2)
SOB R4,40$
MOV R0,R2
ROR R2 ; ROTATE PATTERN
ROL R1
ROR R0
BR 10$
SUPERE:
BOOT:
CLR R3 ; UNIT
1$: MOVB (R2)+,R1
BEQ BOOTRK ; DEFAULT DEVICE IS RK0
CMPB R1,#40
BEQ 1$
CMPB R1,#'R
BEQ 5$
MOV #BADBOO,R0
JSR PC,PRINT
RTS PC
5$: MOVB (R2)+,R1 ; HOPEFULLY K, L OR P
7$: MOVB (R2)+,R0 ; DIGIT
BEQ 9$
CMPB R0,#40
BEQ 9$
CMPB R0,#'7
BGT 11$
SUB #'0,R0
BLT 11$
ASL R3
ASL R3
ASL R3
BIS R0,R3 ; PUT DIGIT INTO UNIT
BR 7$
9$: CLR R2
MOV #137,(R2)+ ; STORE "JMP @#140000" INSTRUCTION AT ADDRESS 0
MOV #START,(R2)+
MOV #START,(R2)+ ; STORE #140000 IN VECTOR 4, IN CASE OF TRAP TO 4
CLR (R2)+
CMPB R1,#'K
BEQ BOOTRK
CMPB R1,#'L
BEQ BOOTRL
CMPB R1,#'P
BEQ BOOTRP
11$: MOV #UNKMSG,R0
JSR PC,PRINT
RTS PC
RLCS=174400
BOOTRL:
RESET
SWAB R3 ; UNIT NUMBER
MOV #RLCS,R1 ; CSR
MOV #13,4(R1) ; CLR ERR
BIS #4,R3 ; UNIT+GSTAT
MOV R3,(R1) ; ISSUE CMD
TSTB (R1) ; WAIT
BPL .-2
CLRB R3
BIS #10,R3 ; UNIT+RDHDR
MOV R3,(R1) ; ISSUE CMD
TSTB (R1) ; WAIT
BPL .-2
MOV 6(R1),R2 ; GET HDR
BIC #77,R2 ; CLR SECTOR
INC R2 ; MAGIC BIT
MOV R2,4(R1) ; SEEK TO 0
CLRB R3
BIS #6,R3 ; UNIT+SEEK
MOV R3,(R1) ; ISSUE CMD
TSTB (R1) ; WAIT
BPL .-2
CLR 2(R1) ; CLR BA
CLR 4(R1) ; CLR DA
MOV #-512.,6(R1) ; SET WC
CLRB R3
BIS #14,R3 ; UNIT+READ
MOV R3,(R1) ; ISSUE CMD
TSTB (R1) ; WAIT
BPL .-2
BIC #377,(R1)
CLR R2
CLR R3
CLR R4
CLR R5
CLR PC
RKDA=177412
READGO=5
BOOTRK:
RESET
SWAB R3 ; UNIT NUMBER
ASL R3
ASL R3
ASL R3
ASL R3
ASL R3
MOV #RKDA,R1 ; CSR
MOV R3,(R1) ; LOAD DA
CLR -(R1) ; CLEAR BA
MOV #-256.*2,-(R1) ; LOAD WC
MOV #READGO,-(R1) ; READ & GO
CLR R2
CLR R3
CLR R4
CLR R5
TSTB (R1)
BPL .-2
CLRB (R1)
CLR PC
RPCSR=0176700
BOOTRP:
RESET
MOV #RPCSR, R1
MOV #0000040, 10(R1) ; RESET
MOV R3, 10(R1) ; SET UNIT
MOV #0000021, (R1) ; PACK ACK
MOV #0010000, 32(R1) ; 16B MODE
MOV #-512., 2(R1) ; SET WC
CLR 4(R1) ; CLR BA
CLR 6(R1) ; CLR DA
CLR 34(R1) ; CLR CYL
MOV #0000071, (R1) ; READ
TSTB (R1) ; WAIT
BPL .-2
CLRB (R1)
MOV R3,R0
CLR PC
.END START