.SBTTL	RP04 CONSOLE SELECTION, 5-AUG-75

$RP:	TTISDO			;GET RP04 SELECTION DIGIT
	CMP	R0,#7		;MUST BE 0 TO 7
	BLE	1$
	JMP	$CMDE

1$:	MOV	R0,RPUNIT	;SAVE
	MOV	#1,DEVTYP	;SET RP04 MODE

	RPLOAD			;INIT & LOAD PACK
	BCS	$RPERR

2$:	JMP	$KONSL

.SBTTL	RP04 FILE DIRECTORY LOOKUP

RPFIL:	RPFILE
	BCS	1$
	JMP	DTRPLD
1$:	JMP	$NONXF

$RPFILE:CLR	RPEOF		;CLEAR END-OF-FILE
	ASCR50			;CONVERT FILE.EXT TO RAD50
	  NAMBF
	  NAMRAD
	BCC	1$
	$PMSG			;NAME.EXT ERR
	  $$NAM
	BR	$RPERX

1$:	MOV	#NAMRAD,R0
	MOV	#FILDSB,R1
	RPLKUP			;LOOK UP FILE IN DIRECTORY
	BCC	3$

	CMP	#-24,R0
	BNE	$RPERR
	EXITERR

3$:	EXIT
;RP04 ERROR REPORTER

$RPERR:	PUSH	R0
	PMSG	<?RP04 ERROR >
	POP	R0
	NEG	R0
	MOV	R0,R1
	PNTOCS			;PRINT ERROR STATUS WORD
	PNTCI
	", 
	DEC	R1
	SL	R1,1
	MOV	RPERTB(R1),R0
	PNTAL			;PRINT ERROR REASON
$RPERX:	JMP	$CNTLC

RPERTB:	RPER1
	RPER2
	RPER3
	RPER4
	RPER5
	RPER6
	RPER7
	RPER10
	RPER11
	RPER12
	RPER13
	RPER14
	RPER15
	RPER16
	RPER17
	RPER20
	RPER21
	RPER22
	RPER23
	RPER24
	RPER25
;RP04 ERROR MESSAGES

RPER1:	.ASCIZ	%UNIT #%
RPER2:	.ASCIZ	%UNAVAIL%
RPER4:
RPER5:
RPER3:	.ASCIZ	%DRV INIT%
RPER6:	.ASCIZ	%HOME BLK RD%
RPER7:	.ASCIZ	%NO HOME BLK%
RPER10:	.ASCIZ	%FILE SYS NAME%
RPER11:	.ASCIZ	%NO INDEX%
RPER12:	.ASCIZ	%NO DIR FILE%
RPER13:	.ASCIZ	%PAST EOF%
RPER20:
RPER14:	.ASCIZ	%POS%
RPER15:	.ASCIZ	%READ ERR%
RPER16:	.ASCIZ	%ALLOC CNG%
RPER17:	.ASCIZ	%BUFSIZ%
RPER21:	.ASCIZ	%INSUFF ALLOC%
RPER22:	.ASCIZ	%DIR REWRT%
RPER23:	.ASCIZ	%DATA WRT%
RPER24:	.ASCIZ	%EOF%
RPER25:	.ASCIZ	%RAD50%
.EVEN
.SBTTL	RP04 FILE RENAME

;COMMAND IS:
;	RENM:FILE.EXT FILE1.EXT

$RE:	TTICHR
	CMPB	#'N,R0
	BNE	1$
	TTICHR
	CMPB	#'M,R0
	BEQ	2$
1$:	JMP	$CMDER

2$:	TTITRM
	NAMEXT			;SETUP CURRENT FILE NAME.EXT

	RPFILE			;FIND AND SETUP FILE
	BCC	4$
	JMP	$NONXF

4$:	NAMEXT			;SETUP NEW FILE NAME.EXT

	ASCR50			;CONVERT NEW FILE.EXT TO RAD50
	  NAMBF
	  NAMRAD
	 BCS	1$		;NAME.EXT ERROR

	MOV	#WRTBAK,R5	;POINTER TO WRITE-BACK INFO TO R5

	MOV	(R5)+,R4	;GET CORE ADDRESS OF FILE DESCRIPTOR
	MOV	#NAMRAD,R3
	MOV	(R3)+,(R4)+	;TRANSFER NEW RAD50 FILE NAME.EXT
	MOV	(R3)+,(R4)+	;TO CURRENT FILE DESCRIPTOR BLOCK
	MOV	(R3),(R4)

	MOV	(R5)+,CYLNDR
	MOV	(R5)+,TRKSCT

	RPWRIT			;REWRITE DIRECTORY BLOCK
	 BCC	3$
	MOV	#-22,R0
	RPERROR

3$:	JMP	$CONSL
.SBTTL	ASCR50	ASCII TO RAD50 CONVERSION ROUTINE

;CALL:
;	ASCR50
;	  ASCII ADDRESS
;	  RAD50 ADDRESS
;NINE BYTES OF ASCII INPUT
;THREE WORDS OF RAD50 OUTPUT

$ASCR50:ADD	#4,12(SP)	;RETURN OVER TRAILING PARAMETERS
	PUSH	R0
	MOV	$EMADR,R5
	MOV	(R5)+,R1	;SETUP ASCII ADDRESS
	MOV	(R5),R4		;SETUP RAD50 STORAGE ADDRESS
	MOV	#066600,R3
1$:	CLR	(R4)		;RESULT WORD
2$:	MOV	#30$,R0		;SETUP SCAN TABLE
3$:	MOVB	(R0)+,R2	;PUT CONVERSION IN R2
	BEQ	20$		;IF END OF TABLE, ERROR
	CMPB	(R1),(R0)+	;COMPARE ASCII CHAR
	BLO	20$		;IF LESS THAN TABLE ENTRY, ERROR
	CMPB	(R1),(R0)+
	BHI	3$		;LOOP, HAVEN'T FOUND YET
	MOVB	(R1)+,R0	;FOUND, ASCII CHAR TO R0
	ADD	R2,R0		;CONVERT
	ASL	(R4)
	ASL	(R4)
	ASL	(R4)
	ADD	(R4),R0
	ASL	(R4)
	ASL	(R4)
	ADD	R0,(R4)
	ASL	R3		;SHIFT RAD50 WORD COUNTER
	BMI	2$		;NOT DONE WITH THIS RAD50 YET
	BEQ	10$		;IF 0, ALL DONE
	TST	(R4)+		;STEP TO NEXT RAD50 WORD
	BR	1$		;GO DO NEXT
10$:	POP	R0
	EXIT
20$:	POP	R0
	EXITERR

30$:	.BYTE	-40,' ,' 	;SPACE
	.BYTE	-11,'$,'$	;DOLLAR SIGN
	.BYTE	-22,'.,'.	;PERIOD
	.BYTE	-22,'0,'9	;DIGITS
	.BYTE	-100,'A,'Z	;UPPER CASE LETTERS
	.ENABL	LC
	.BYTE	-140,'a,'z	;LOWER CASE LETTERS
	.BYTE	0		;INDICATE THE END OF THE TABLE
	.EVEN
.SBTTL	RPLOAD	RP04 LOAD PACK (READ HOME BLOCK) ROUTINE

$RPLOAD:RPINIT			;INITIALIZE RP04
	BCS	10$

	MOV	#-6,R5
	CLR	CYLNDR
	MOV	#1,TRKSCT
	MOV	#DVBUF,BUFADR
	MOV	#BLKSIZ,BUFSIZ
	MOV	#-BLKSIZ,WRDCNT
	RPREAD			;READ HOME BLOCK
	BCS	9$		;-6 ERROR
	DEC	R5

;SAVE INFORMATION ABOUT THE INDEX FILE & FILE DIRECTORY

	MOV	#DVBUF+<^D105*2>,R1
	MOV	#RPIXCY,R2
1$:	MOV	(R1)+,(R2)+
	CMP	R1,#DVBUF+<^D111*2>
	BLO	1$

;CHECK THAT THIS IS REALLY THE HOME BLOCK

	CMP	DVBUF,#105755	;LAST 16 BITS OF "HOM" IN SIXBIT
	BNE	9$		;-7, BRANCH IF NOT HOM BLOCK
	DEC	R5

;CHECK THAT THIS PACK CONTAINS OUR FILE SYSTEM (KLFEDDCS)

	MOV	#DVBUF+<^D98*2>,R1
	MOV	#FSNAME,R2
2$:	CMP	(R1)+,(R2)+
	BNE	9$		;-10, BRANCH IF FILE SYSTEM NAME IS INCORRECT
	CMP	R1,#DVBUF+<^D104*2>
	BLO	2$
	DEC	R5
	TST	RPIXCY		;DOES INDEX FILE EXIST?
	BLE	9$		;-11, BRANCH IF INDEX FILE DOES NOT EXIST
	DEC	R5
	TST	RPFDCY		;DOES FILE DIRECTORY EXIST?
	BLE	9$		;-12, BRANCH IF FILE DIRECTORY DOES NOT EXIST
	EXIT			;INDICATE SUCCESS

9$:	MOV	R5,R0		;PUT ERROR CODE IN R0
10$:	SETFLG			;INDICATE FAILURE
	  RPUNIT
11$:	EXITERR

FSNAME:	.ASCII	/KLFEDDCS    /	;FILE SYSTEM NAME
.SBTTL	RPFIND	FIND FILE IN RP04 DIRECTORY

;R0 = POINTER TO FILE NAME IN RAD50
;R1 = POINTER TO RETURN STORE BLOCK
;	CORE ADR OF FILE DESCRIPTOR BLOCK
;	CYLINDER NUMBER
;	TRACK/SECTOR NUMBER

$RPFIND:MOV	R0,R4		;SAVE FILE NAME POINTER
	MOV	R1,R5		;SAVE RETURN POINTER
	MOV	#DVBUF,BUFADR
	MOV	#-BLKSIZ,WRDCNT
	MOV	#BLKSIZ,BUFSIZ
	MOV	#FILDSB,R3	;SETUP FILE DESCRIPTOR POINTER
	MOV	#RPFDCY,R2	;SETUP DIRECTORY START

	MOV	(R2)+,4*2(R3)
	MOV	(R2)+,5*2(R3)
	MOV	(R2),R0		;CHANGE DIR BLOCK COUNT TO
	SHIFTL			;WORD COUNT
	  8.
	MOV	R0,9.*2(R3)
	CLR	8.*2(R3)

	MOV	R3,R2
	ADD	#FDESIZ*2,R2
	CLR	(R2)+		;CLEAR CURRENT POSITION
	CLR	(R2)

1$:	MOV	R3,R0
	RPRDFL			;READ DIRECTORY DATA BLOCK
	 BCS	4$		;ERROR

	MOV	(R0)+,R2	;DATA BUFFER POSITION
	MOV	(R0),R1		;BYTE COUNT
2$:	CMP	(R2),(R4)	;COMPARE DIRECTORY ENTRY
	BNE	3$		;AND REQUESTED FILE
	CMP	1*2(R2),1*2(R4)
	BNE	3$
	CMP	2*2(R2),2*2(R4)
	BNE	3$		;NOT THIS ENTRY

	MOV	R2,(R5)+	;RETURN CORE ADDRESS OF DESCRIPTOR BLOCK
	MOV	CYLNDR,(R5)+	;RETURN CYLINDER NUMBER
	MOV	TRKSCT,(R5)+	;RETURN TRACK/SECTOR NUMBERS
	EXIT			;"SUCCESS" RETURN

3$:	ADD	#FDESIZ*2,R2	;FINISHED THIS DIRECTORY BLOCK ?
	SUB	#FDESIZ*2,R1
	BHI	2$		;NO
	BR	1$		;YES, GO READ NEXT

4$:	CMP	#1,R0		;EOF ?
	BNE	5$		;NO, RETURN ERROR CODE
	MOV	#-24,R0		;YES, RETURN EOF CODE
5$:	EXITERR
.SBTTL	RPLKUP	RP04 FILE DIRECTORY LOOKUP ROUTINE

;R0/ POINTER TO FILENAME IN RAD50
;R1/ STORE ADDRESS FOR FILE DESCRIPTOR

;FILE DESCRIPTOR BLOCK
;	 0/ FILENAME
;	 1/   "
;	 2/ FILE EXT
;	 3/ CREATION DATE
;	 4/ PHYSICAL BLOCK NUMBER
;	 5/   "
;	 6/ NUMBER OF WORDS ALLOCATED
;	 7/  "
;	 8/ NUMBER OF WORDS WRITTEN
;	 9/  "
;	10/ PDP-11 LOAD ADDRESS
;	11/ PDP-11 START ADDRESS
;	12/ FILE TYPE & FILE STATUS
;	13/ CHECKSUM
;	14/ 0
;	15/ 0
;	16/ CURRENT POSITION
;	17/  "

$RPLKUP:MOV	R1,R5		;SAVE FILE DESCRIPTOR POINTER
	MOV	#WRTBAK,R1

	RPFIND			;FIND FILE
	BCS	2$		;NOT THERE

	MOV	#FDESIZ,R2	;TRANSFER FILE INFO
	MOV	(R1),R1
1$:	MOV	(R1)+,(R5)+	;TO FILE DESCRIPTOR BLOCK
	DEC	R2
	BNE	1$

	CLR	(R5)+		;SET CURRENT POSITION AT ZERO
	CLR	(R5)+
	EXIT

2$:	EXITERR
.SBTTL	RPRDFL	READ A FILE (ON THE RP04)

;R0 = POINTER TO FILE DESCRIPTOR

$RPRDFL:MOV	R0,R2		;SETUP FILE DESCRIPTOR POINTER
	MOV	R2,R4
	ADD	#^D16*2,R4	;R4 POINTS TO CURRENT POSITION BLOCK
	MOV	BUFSIZ,R3	;BUFFER SIZE TO R3

	MOV	^D8*2(R2),R0	;R0 = M.S. NUMBER OF WORDS WRITTEN
	MOV	^D9*2(R2),R1	;R1 = L.S. NUMBER OF WORDS WRITTEN
	SUB	2(R4),R1	;R1 = L.S. NUMBER OF WORDS REMAINING
	SBC	R0		;PROPAGATE THE "BORROW"
	SUB	(R4),R0		;R0 = M.S. NUMBER OF WORDS REMAINING
	BLT	40$		;BRANCH IF PAST EOF (ERROR)

	BGT	10$		;BRANCH IF MORE THAN 2**16 WORDS REMAIN

	TST	R1		;NOW LOOK AT L.S. # OF WORDS REMAINING
	BEQ	60$		;BRANCH IF AT EOF

	CMP	R1,R3		;COMPARE REMAINING WORDS WITH "BUFSIZ"
	BHI	10$		;BRANCH IF REMAINING WORDS IS LARGER

	MOV	R1,R3		;REMAINING WORDS IS SMALLER (OR EQUAL)
	BR	15$		;AVIOD TRUNCATING THE BUFFER SIZE

10$:	BIC	#BLKSIZ-1,R3	;TRUNCATE TO A MULTIPLE OF THE BLOCK SIZE

15$:	BIT	#BLKSIZ-1,2(R4)	;IS CURRENT POSITION A MULTIPLE OF BLOCK SIZE?
	BNE	50$		;BRANCH IF NOT A MULTIPLE OF BLOCK SIZE

	MOV	4*2(R2),CYLNDR	;CYLINDER NUMBER OF START OF FILE
	MOV	5*2(R2),TRKSCT	;TRACK,SECTOR OF START OF FILE
	MOV	(R4),R2		;R2 = M.S. CURRENT POSITION
	SWAB	R2
	BISB	3(R4),R2
	MOV	R2,OFFSET

	RPADDR			;COMPUTE BLOCK # TO BE READ
	NEG	R3
	MOV	R3,WRDCNT	;SETUP WORD COUNT
	NEG	R3

	RPREAD			;READ FILE DATA BLOCK
	BCS	70$		;READ ERROR

	ADD	R3,2(R4)	;UPDATE L.S. CURRENT POSITION
	ADC	(R4)		;PROPAGATE CARRY INTO M.S. CURRENT POSITION
	ASL	R3		;CONVERT WORDS READ TO BYTES
75$:	MOV	R3,$RPINFO+2	;AND STORE AS BYTE COUNT ARGUMENT
	MOV	BUFADR,$RPINFO	;STORE BUFFER ADDRESS
	MOV	#$RPINFO,R0
	EXIT

40$:	MOV	#-13,R0		;WE SEEM TO BE PAST THE EOF
	BR	30$
50$:	MOV	#-14,R0		;WE WERE POSITIONED AT A NON-MULTIPLE OF BLKSIZ
	BR	30$
60$:	MOV	#1,R0		;WE WERE ALREADY AT EOF
	BR	30$
70$:	MOV	#-15,R0		;INDICATE THAT NO DATA WAS READ
30$:	EXITERR
.SBTTL	RPWRFL	WRITE A FILE (ON THE RP04)

;R0 = POINTER TO FILE DESCRIPTOR
;BUFADR = ADDRESS OF BUFFER
;BUFSIZ = NUMBER OF WORDS TO BE WRITTEN
;RPEOF = BIT15=0, DON'T WRITE EOF; BIT15=1, WRITE EOF

$RPWRFL:MOV	R0,R2
	MOV	^D16*2(R2),R0	;R0 = M.S. CURRENT POSITION
	MOV	^D17*2(R2),R1	;R1 = L.S. CURRENT POSITION
	MOV	BUFSIZ,R3
	BEQ	70$		;BRANCH IF THE WORD COUNT IS ZERO

	TST	RPEOF		;WRITING AN EOF ?
	BMI	1$		;YES

	BIT	#BLKSIZ-1,R3	;IS BUFSIZ A MULTIPLE OF BLKSIZ?
	BNE	RPWER1		;BRANCH IF IT IS NOT A MULTIPLE

1$:	BIT	#BLKSIZ-1,R1	;IS THE CURRENT POSITION A MULTIPLE?
	BNE	RPWER2		;BRANCH IF IT IS NOT A MULTIPLE

	MOV	R0,R4		;R4 = M.S. CURRENT POSITION
	ADD	R3,R1		;R1 = L.S. NEW POSITION
	ADC	R0		;R0 = M.S. NEW POSITION
	CMP	^D6*2(R2),R0	;COMPARE WITH WORDS ALLOCATED
	BGT	5$		;BRANCH IF MORE WORDS ALLOCATED

	BLT	RPWER3		;BRANCH IF NOT ENOUGH WORDS ALLOCATED

	CMP	^D7*2(R2),R1	;ITS CLOSE, LOOK FURTHER
	BLO	RPWER3		;BRANCH IF NOT ENOUGH WORDS ALLOCATED

5$:	SWAB	R4
	BISB	<^D17*2>+1(R2),R4
	MOV	R4,OFFSET
	MOV	^D4*2(R2),CYLNDR ;CYLINDER NUMBER
	MOV	^D5*2(R2),TRKSCT ;TRACK/SECTOR NUMBERS
	RPADDR
	NEG	R3
	MOV	R3,WRDCNT
	NEG	R3

	RPWRIT			;WRITE DATA BLOCK
	BCS	RPWER5
	ADD	R3,^D17*2(R2)	;COMPUTE NEW CURRENT POSITION
	ADC	^D16*2(R2)	;PROPAGATE CARRY
	MOV	^D17*2(R2),^D9*2(R2) ;SET EOF AT CURRENT POSITION
	MOV	^D16*2(R2),^D8*2(R2) ;(M.S. ALSO)

70$:	TST	RPEOF		;ARE WE WRITING AN EOF
	BPL	RPWEX		;NO
	MOV	R2,R0
	MOV	#WRTBAK,R1

	MOV	#DVBUF,BUFADR
	MOV	#-BLKSIZ,WRDCNT
	MOV	#BLKSIZ,BUFSIZ

	MOV	2(R1),CYLNDR	;SETUP SAME DIRECTORY BLOCK
	MOV	4(R1),TRKSCT

	RPREAD			;READ CURRENT FILE DIRECTORY BLOCK
	BCS	RPWER4

	MOV	(R1)+,R3
	CMP	^D6*2(R2),^D6*2(R3)
	BNE	RPWER0		;BRANCH IF ALLOCATION IS DIFFERENT
	CMP	^D7*2(R2),^D7*2(R3)
	BNE	RPWER0		;BRANCH IF ALLOCATION IS DIFFERENT

	MOV	#FDESIZ,R4
71$:	MOV	(R2)+,(R3)+
	DEC	R4
	BNE	71$

	MOV	(R1)+,CYLNDR
	MOV	(R1)+,TRKSCT

	RPWRIT			;REWRITE DIRECTORY
	BCS	RPWER4

RPWEX:	EXIT			;SUCCESSFUL COMPLETION WITH NO EOF

RPWER0:	MOV	#-16,R0		;ATTEMPT TO CHANGE FILE'S ALLOCATION
	BR	RPWERX
RPWER1:	MOV	#-17,R0		;BUFSIZ IS NOT A MULTIPLE OF BLOCK SIZE
	BR	RPWERX
RPWER2:	MOV	#-20,R0		;CURRENT POS. IS NOT A MULTIPLE OF BLOCK SIZE
	BR	RPWERX
RPWER3:	MOV	#-21,R0		;INSUFFICIENT ALLOCATION TO COMPLETE THIS WRITE
	BR	RPWERX
RPWER4:	MOV	#-22,R0		;DIRECTORY REWRITE FAILURE
	BR	RPWERX
RPWER5:	MOV	#-23,R0		;DATA BLOCK WRITE FAILURE

RPWERX:	EXITERR
.SBTTL	RPINIT	STORES UNIT NUMBER & TRIES TO SET VOLUME VALID

$RPINIT:MOV	#-1,R0
	MOV	RPUNIT,R2	;CHECK RP04 UNIT #
	BIT	#^C7,R2
	BNE	2$		;-1 ERROR, BAD

	DEC	R0
	MOV	RPRH11,R1
	MOV	#RPCLR,RPCS2(R1) ;CLEAR RP04
	MOV	R2,RPCS2(R1)	;SELECT
	BIT	#RPDVA,(R1)	;IS DRIVE AVAILABLE ?
	BEQ	2$		;-2 ERROR, NO

	DEC	R0
	MOV	RPDS(R1),R2	;READ STATUS
	COM	R2
	BIC	#^C<RPMOL!RPDPR!RPDRY>,R2
	BNE	2$		;-3 ERROR, DRIVE ERROR

	DEC	R0
	MOV	#RPPRST,(R1)	;SET READ-IN PRESET
1$:	TSTB	(R1)		;WAIT FOR CONTROLLER READY
	BPL	1$

	BIT	#<RPTRE!RPMCPE>,(R1)
	BNE	2$		;-4 ERROR, DRIVE ERROR

	DEC	R0
	BIT	#<RPATA!RPERR>,RPDS(R1)
	BNE	2$		;-5 ERROR, DRIVE ERROR

3$:	EXIT

2$:	BIS	#100000,RPUNIT	;ERROR, FORCE RESELECT
	EXITERR

.SBTTL	RPBASE	RETURN RP04 PARAMETER BLOCK BASE ADDRESS

$RPBASE:MOV	#FILDSB,R0
	EXIT
.SBTTL	RPREAD & RPWRIT, RP04 READ & WRITE I/O ROUTINES

$RPWRIT:MOV	#RPWTFN,R5	;SETUP WRITE FUNCTION
	CLR	R4
	BR	RPFUNC

$RPREAD:MOV	#RPRDFN,R5	;SETUP READ FUNCTION
	MOV	#10.,R4		;10 RETRIES

RPFUNC:	JSR	PC,$PTTYC
	TST	RPUNIT		;VALID UNIT ?
	BMI	2$		;NO

	MOV	RPRH11,R1
5$:	MOV	RPUNIT,RPCS2(R1) ;SELECT DRIVE
	BIT	#RPDVA,(R1)	;IS DRIVE AVAILABLE ?
	BEQ	2$		;NO

	MOV	RPDS(R1),R2	;CHECK DRIVE STATUS
	COM	R2
	BIC	#^C<RPMOL!RPDPR!RPDRY!RPVV>,R2
	BNE	2$		;ERROR

	MOV	CYLNDR,RPDC(R1)	;START DRIVE OPERATION
	MOV	TRKSCT,RPDA(R1)
	MOV	BUFADR,RPBA(R1)
	MOV	WRDCNT,RPWC(R1)
	MOV	R5,(R1)

1$:	BIT	#<RPTRE!RPMCPE!RPRDY>,(R1)
	BEQ	1$		;WAIT FOR COMPLETION OR ERROR

	BIT	#<RPTRE!RPMCPE>,(R1)
	BNE	2$		;ERROR

	BIT	#<RPATA!RPERR>,RPCS2(R1)
	BNE	4$		;ERROR

3$:	EXIT			;COMPLETED

2$:	EXITERR

4$:	DEC	R4		;RETRY READ ERRORS, 10 TIMES
	BLE	2$		;HARD ERROR
	MOV	#RPCLR,RPCS2(R1) ;CLEAR RP04
	BR	5$		;TRY AGAIN
.SBTTL	RPADDR	ADDS OFFSET TO AN RP04 PHYSICAL ADDRESS

$RPADDR:MOV	CYLNDR,R0	;SETUP INITIAL VALUES
	MOV	TRKSCT,R1
	MOV	OFFSET,R2

	MOVB	R1,R3		;COMPUTE NEW POSITION
	CLRB	R1
	SWAB	R1
	ADD	R3,R2
1$:	BPL	2$
	DEC	R0
	ADD	#^D19*^D20,R2
	BR	1$
2$:	SUB	#^D19*^D20,R2
	BLT	3$
	INC	R0
	BR	2$
3$:	ADD	#^D19*^D20,R2
4$:	SUB	#^D20,R2
	BLT	5$
	INC	R1
	BR	4$
5$:	ADD	#^D20,R2
6$:	SUB	#^D19,R1
	BLT	7$
	INC	R0
	BR	6$
7$:	ADD	#^D19,R1
	SWAB	R1
	BISB	R2,R1

	MOV	R0,CYLNDR	;RETURN NEW POSITION
	MOV	R1,TRKSCT
	EXIT