;	CSTAT		Dynamic disk cache status for Alpha's DCACHE.SYS
;	Author:		Irwin M. Goldstein
;	Date written:	10/15/86

	SEARCH	SYS			; system macros
	SEARCH	SYSSYM			; system symbols
	SEARCH	TRM			; terminal symbols
;	COPY	TABMAC			; special screen functions macro

;THIS IS TABMAC   |  |
;                 V  V
;
DEFINE	PRTTAB	AA,BB		;PRINT TAB (#,#)
	MOVB	#AA,D1
	LSLW	D1,#10
	MOVB	#BB,D1
	TCRT
ENDM


;***	Macro  for displaying contents of a register &
;	   clearing to end of line

DEFINE	DISPLY	REG
	MOV	REG,D1
	DCVT	0,OT$TRM
	PRTTAB	-1.,9.
ENDM

;***	Offsets into CACHE.BUF:
;	    (determined by FIXing CACHE.LIT)

TOTBUF	=	16			; total buffers (word)
ULKBUF	=	20			; unlocked buffers (word)
LOKBUF	=	22			; locked buffers (word)
TOTRED	=	24			; total reads (long word)
CACRED	=	30			; cache reads (long word)
CASTAT	=	54			; cache status (word)

;***	Work area:
;	    memory area for saving cache status

	ASECT
	.=0
TBSAV:	BLKW	1			; total buffers
UBSAV:	BLKW	1			; unlocked buffers
LBSAV:	BLKW	1			; locked buffers
TRSAV:	BLKL	1			; total reads
DRSAV:	BLKL	1			; disk reads
CRSAV:	BLKL	1			; cache reads
CSSAV:	BLKW	1			; cache status
CRFP:	BLKW	3			; cache reads in floating point
TRFP:	BLKW	3			; total reads in floating point
MEMSIZ:					; defines size of memory area we need
	PSECT
	.=0

	PHDR	-1,0,PH$REE!PH$REU

;***	Locate CACHE buffer in system memory; If it's not there - error!

	SRCH	BUFNAM,A0		; get address of cache buffer
	BEQ	CSTAT			; buffer located, continue

	TYPECR	<?CACHE not installed>
	EXIT

;***	Initialize:  Set image mode with echo off, allocate workspace:

CSTAT:	JOBIDX	A5			; index our JCB
	MOV	JOBTRM(A5),A5		; get address of terminals status word
	ORW	#T$IMI!T$ECS,@A5	; set image mode, echo off
	GETIMP	MEMSIZ,A1		; get some memory for work space

;***	Start display stats; clear workspace & screen, display screen mask:

AGAIN:	CLEAR	@A1,MEMSIZ		; clear the work space
	PRTTAB	-1,0			; clear screen
	PRTTAB	-1,29.			; turn cursor off
	PRTTAB	-1,11.			; reduced intensity
	TTYL	SCREEN			; display status mask
	PRTTAB	-1,12.			; normal intensity

;***	Loop until stopped, checking status & updating screen as needed:

LOOP:	CLR	D0			; pre-clear display register

;	Display total buffers if they changed from last time:

CHKTB:	MOVW	TOTBUF(A0),D0		; get total buffers
	CMPW	D0,TBSAV(A1)		; did they change?
	BEQ	CHKLB			;   no - check locked buffers
	MOVW	D0,TBSAV(A1)		;   yes - save new value
	PRTTAB	3.,22.			; position cursor
	DISPLY	D0			; display # of buffers

;	Display unlocked buffers if they changed from last time:

CHKUB:	MOVW	ULKBUF(A0),D0		; get unlocked buffers
	CMPW	D0,UBSAV(A1)		; did they change?
	BEQ	CHKLB			;   no - check locked  buffers
	MOVW	D0,UBSAV(A1)		;   yes - save new value
	PRTTAB	4.,22.			; position cursor
	DISPLY	D0			; display # of unlocked buffers

;	Display locked buffers if they changed from last time:

CHKLB:	MOVW	LOKBUF(A0),D0		; get locked buffers
	CMPW	D0,LBSAV(A1)		; did they change?
	BEQ	CHKTR			;   no - check unlocked buffers
	MOVW	D0,LBSAV(A1)		;   yes - save new value
	PRTTAB	5.,22.			; position cursor
	DISPLY	D0			; display # of locked buffers

;	Display efficiency stats if total reads have changed from
;	last time:

;	D2 = total reads
;	D3 = cache reads
;	D4 = disk reads

CHKTR:	MOV	TOTRED(A0),D2		; get total reads
	CMP	D2,TRSAV(A1)		; did they change?
	JEQ	CHKCS			;   no - check cache status
	MOV	D2,TRSAV(A1)		;   yes - save new value
	MOV	CACRED(A0),D3		; get cache reads
	MOV	D2,D4			; calculate disk reads by
	SUB	D3,D4			;   subtracting cache reads from total reads

	PRTTAB	7.,22.			; position cursor
	DISPLY	D2			; display total reads

;	Display cache reads if they changed from last time:

	CMP	D3,CRSAV(A1)		; did cache reads change?
	BEQ	CHKDR			;   no - check disk reads
	MOV	D3,CRSAV(A1)		;   yes - save new value
	PRTTAB	8.,22.			; position cursor and
	DISPLY	D3			; display cache reads

;	Display disk reads if they changed from last time:

CHKDR:	CMP	D4,DRSAV(A1)		; disk disk reads change?
	BEQ	CHKHIT			;   no - check hit rate
	MOV	D4,DRSAV(A1)		;   yes - save new value
	PRTTAB	9.,22.			; position cursor and
	DISPLY	D4			; display disk reads

;	Display the hit rate if total reads have changed:

CHKHIT:	LEA	A2,TRFP(A1)		; index total reads in FP
	LEA	A3,CRFP(A1)		; index cache reads in FP
	FLTOF	D2,@A2			; convert total reads to FP
	FLTOF	D3,@A3			; convert cache reads to FP
	FDIV	A2,A3			; divide total reads into cache reads
	FPWR	@A3,#2			; multiply result by 100 to get %
	PRTTAB	11.,22.			; postion cursor
	FCVT	@A3,4,OT$FIX!OT$TRM,1,0	; display hit rate
	TYPE	%			;  as a percentage

;	Redisplay all operation flags if they have changed:

CHKCS:	MOVW	CASTAT(A0),D0		; get status flags
	CMPW	D0,CSSAV(A1)		; did they change?
	JEQ	PAUSE			;   no - pasue & then loop back for more status
	MOVW	D0,CSSAV(A1)		;   yes - save new value

	PRTTAB	16.,22.			; position cursor
	LEA	A2,ONTXT		; index ON
	BTST	#0,D0			; is cache on?
	BNE	CON			;   yes - say so
	LEA	A2,OFFTXT		;   no - index OFF
CON:	TTYL	@A2			; display OFF or ON

	PRTTAB	17.,22.			; postion cursor
	LEA	A2,ONTXT		; index ON
	BTST	#1,D0			; is read restriction on?
	BNE	RRON			;   yes - say so
	LEA	A2,OFFTXT		;   no - index OFF
RRON:	TTYL	@A2			; display OFF or ON

	PRTTAB	18.,22.			; position cursor
	LEA	A2,ONTXT		; index ON
	BTST	#2,D0			; is random restrtiction on?
	BNE	RNRON			;   yes - say so
	LEA	A2,OFFTXT		;   no - index OFF
RNRON:	TTYL	@A2			; display OFF or ON

	PRTTAB	19.,22.			; position cursor
	LEA	A2,ONTXT		; index ON
	BTST	#3,D0			; is lock restriction on?
	BNE	LRON			;   yes - say so
	LEA	A2,OFFTXT		;   no - index OFF
LRON:	TTYL	@A2			; display OFF or ON

	PRTTAB	20.,22.			; position cursor
	LEA	A2,ONTXT		; index ON
	BTST	#4,D0			; is MFD locking on?
	BNE	MFDON			;   yes - say so
	LEA	A2,OFFTXT		;   no - index OFF
MFDON:	TTYL	@A2			; display OFF or ON

	PRTTAB	21.,22.			; position cursor
	LEA	A2,ONTXT		; index ON
	BTST	#5,D0			; is UFD locking on?
	BNE	UFDON			;   yes - say so
	LEA	A2,OFFTXT		;   no index OFF
UFDON:	TTYL	@A2			; display OFF or ON

PAUSE:	TCKI				; has anything been typed?
	BNE	SNORE			;   no - sleep for a while & repeat
	KBD				;   yes - get character typed
	CMPB	D1,#27.			; ESCape pressed?
	BNE	SNORE			;   no - ignore it
	PRTTAB	23.,25.			; position cursor at bottom
	TYPESP	<Enter command (Q,R):>	; display command prompt
	PRTTAB	-1,28.			; turn cursor on
	KBD	QUIT			; get command
	UCS				; convert to upper case
	CMPB	D1,#'Q			; quit?
	BEQ	QUIT			;   yes - abort
	CMPB	D1,#'R			;   no - replot?
	JEQ	AGAIN			;     yes - start again!
	PRTTAB	-1,29.			;     no - turn cursor off
	PRTTAB	23.,1.			;          put cursor before prompt
	PRTTAB	-1,9.			;          clear prompt

;***	Sleep for a second, then recheck stats:

SNORE:	SLEEP	#10000.			; wait a second
	CTRLC	QUIT			; check for abort
	JMP	LOOP			; loop back for more status

;***	Exit program: move to bottom of screen & clean up:

QUIT:	PRTTAB	23.,1.			; put cursor near the bottom
	PRTTAB	-1,10.			; clear to end of screen
	PRTTAB	-1,28.			; turn cursor on
	EXIT

;***	Constants:

BUFNAM:	RAD50	\CACHE BUF\		; name of cache buffer module

ONTXT:	ASCIZ	\ON \			; text for ON messages
OFFTXT:	ASCIZ	\OFF\			; text for OFF messages

;***	Status screen:

SCREEN:	ASCII	\DISK CACHE STATUS--.\
	BYTE	13.,13.
	ASCII	\      Total buffers:\
	BYTE	13.
	ASCII	\   Unlocked buffers:\
	BYTE	13.
	ASCII	\     Locked buffers:\
	BYTE	13.,13.
	ASCII	\        Total reads:\
	BYTE	13.
	ASCII	\   Reads from cache:\
	BYTE	13.
	ASCII	\    Reads from disk:\
	BYTE	13.,13.
	ASCII	\           Hit rate:\
	BYTE	13.,13.,13.
	ASCII	\OPERATION FLAGS----.\
	BYTE	13.,13.
	ASCII	\           Cache is:\
	BYTE	13.
	ASCII	\   Read restriction:\
	BYTE	13.
	ASCII	\ Random restriction:\
	BYTE	13.
	ASCII	\   Lock restriction:\
	BYTE	13.
	ASCII	\Dynamic MFD locking:\
	BYTE	13.
	ASCII	\Dynamic UFD locking:\
	BYTE	0

	END

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