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decuslib20-02
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decus/20-0057/pfhsno.mac
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00100
00200 TITLE PFHSNO
00300
00400 ENTRY S$$PFZ
00500
00600 SEARCH UUOSYM
00700 SEARCH S$$NDF
00800 SALL
00900
01000
01100 ;*******************************************************************
01200 ;
01300 ;DECSYSTEM-10 PAGE FAULT HANDLER.....MAY 1977
01400 ;
01500 ;REVISED VERSION JULY 1978
01600 ;ADAPTED FOR FASBOL LIBRARY AUGUST 1978
01700 ;
01800 ;
01900 ;NIGEL DERRETT
02000 ;DATALOGISK AFDELING, MATEMATISK INSTITUT, AARHUS UNIVERSITY, DENMARK
02100 ;
02200 ;********************************************************************
02300 ;
02400 ;********************************************************************
02500 ;
02600 ;This page-fault handler uses a sort of "second chance" algorithm.
02700 ;Any pages which have not been accessed for 2 time-slots are regarded
02800 ;as candidates to be shoved out
02900 ;
03000 ;Fasbol programs overwrite the last 1k of core, so the standard
03100 ;page fault handler cannot be used.
03200 ;This handler should be loaded with the user program. It removes
03300 ;the system pfh, if present.
03400 ;
03500 ;Non-VM systems should set the switch P$VM in SDDNDF to zero;
03600 ;VM systems should set it to 1.
03700 ;Systems with both VM and non-VM users will need two versions of FASBOL
03800 ;and FASLIB.
03900 ;
04000 ;To initialise the page fault handler:
04100 ; JSR S$$PFZ##
04200 ;No regs are altered.
04300 ;
04400 ;****************************************************************************
04500
04600
04700 PAGE
04800 ;**********************************************************************
04900 ;
05000 ; DUMMY MODULE FOR NON-VM SYSTEMS
05100 ;
05200 ;**********************************************************************
05300
05400 IFE P$VM<
05500 ; dummy code for non-vm systems
05600
05700 S$$PFZ: 0
05800 JRSTF @ S$$PFZ
05900 >
06000
06100
06200 IFN P$VM<
06300
06400 ; rest of pfh
06500
06600 PAGE
06700 ;**********************************************************************
06800 ;
06900 ; FEATURES
07000 ;
07100 ;**********************************************************************
07200
07300 FTTEST=0 ; switch for producing trace output
07400 FTSHOW=0 ; switch for producing "hello" message
07500 FTNOTM=0 ; switch to disable time interrupts
07600 ; (useful for debugging)
07700
07800
07900 PAGE
08000 ;************************************************************************
08100 ;
08200 ; CONSTANTS
08300 ;
08400 ;************************************************************************
08500
08600 ; Registers
08700 T1=1
08800 T2=2
08900 T3=3
09000 T4=4
09100 PN=5 ; page number
09200 P=6 ; stack pointer
09300
09400 ; ***NOTE***
09500 ; The entry code at START requires the regs to be in this order
09600 ; GETIN, CREATE, and ACCESS require that PN = T4+1
09700 ; Others require that T1-T4 are consecutive.
09800
09900
10000 ; Constants
10100
10200 IFN FTNOTM<
10300 TIMINT=0 ; no time traps
10400 >
10500 IFE FTNOTM<
10600 TIMINT=1000 ; interval between time traps
10700 >
10800
10900 FFLSTA=2 ; initial force level
11000
11100 MAPSIZE=17 ; size of a page map
11200 PAGSIZ=1000 ; size of a page
11300
11400 ALSIZE=20 ; size of argument list for CLRABS
11500
11600 IFN FTTEST,<
11700 STKSIZ=40 ; large stack when testing - for OUTNUM
11800 >
11900 IFE FTTEST,<
12000 STKSIZ=20 ; small stack normally
12100 >
12200
12300
12400 PAGE
12500 ;**********************************************************************
12600 ;
12700 ; MACROS
12800 ;
12900 ;**********************************************************************
13000
13100
13200 DEFINE NOOP <JFCL 0,0>
13300
13400
13500 IFN FTTEST,<
13600 DEFINE TRACE(AC, TEXT)<
13700 IFN AC,< IFN AC-T1 < EXCH T1, AC >
13800 PUSHJ P, OUTNUM
13900 IFN AC-T1,< EXCH T1, AC >
14000 >
14100 OUTSTR [ASCIZ/TEXT
14200 /]
14300 >> ; end IFN FTTEST
14400
14500
14600 IFE FTTEST,<
14700 DEFINE TRACE(AC,TXT)<>
14800 > ; end IFE FTTEST
14900
15000
15100 IFN FTTEST,<
15200 DEFINE ERROR(TEXT)<
15300 JRST [ OUTSTR ERMST
15400 OUTSTR [ASCIZ/TEXT
15500 /]
15600 HALT .
15700 ]
15800 >> ; end IFN FTTEST
15900
16000
16100 IFE FTTEST,<
16200 DEFINE ERROR(TEXT)<
16300 HALT .
16400 >> ; end IFE FTTEST
16500
16600
16700 DEFINE MESSAGE(TEXT)<
16800 OUTSTR [ASCIZ/TEXT
16900 /]
17000 >
17100
17200
17300 PAGE
17400 ;*****************************************************************
17500 ;
17600 ; ENTRY POINT FOR HANDLER WHEN A PAGE FAULT OCCURS
17700 ;
17800 ;*****************************************************************
17900
18000
18100 ; Here starteth the handler proper
18200
18300 PFHSTR: JRST START
18400 FPC: 0 ; PC of page fault word
18500 PFWD: 0 ; page fault word
18600 VTIME: 0 ; virtual time elapsed
18700 PGRATE: 0 ; page rate
18800 PSIVEC: 0 ; PSI vectors
18900 BLOCK 3 ; reserved by DEC
19000
19100
19200 ; Normal entry point
19300 START: SOSE SEMAFO ; check whether we are in the PFH already
19400 START1: ERROR<START1> ; yes - error - the handler is not reentrant
19500
19600 DMOVEM T1,SAVT1 ; save accumulators which we will use
19700 DMOVEM T3,SAVT3 ;
19800 DMOVEM PN,SAVPN ;
19900 MOVE P, STKWD ; Set up stack
20000
20100 SKIPGE PFWD ; has WS changed ?
20200 PUSHJ P, REINIT ; yes - reinitialize
20300
20400 DISPCH: HRRZ T1,PFWD ; get cause
20500 TRACE T1,<Cause of page fault>
20600
20700 SOJE T1, DISP2 ; Unless it is ALLOW-ACCESS
20800 ; get an up-to-date version of the USEDTHISTIME map
20900 MOVE T2, [XWD .PAGGA, UTMBLK]
21000 PAGE. T2, ; get access allowed map
21100 STAER2: ERROR<STAER2> ; nasty!
21200
21300 DISP2: ; T1 = faulttype-1
21400 CAIGE T1, 4 ; if cause is ZERO-PAGE
21500 CAIN T1, 1 ; or non-uuo page not in core
21600 SETOM LASTPC ; then forget LASTPC
21700 ; We are actually doing something useful
21800 ; so we can't be in a dump-mode IO loop.
21900
22000 LDB PN,[POINT 17,PFWD,17]; get page number for fault
22100 TRACE PN,<Fault page number>
22200
22300 PUSHJ P, TABLE(T1) ; dispatch using fault type (T1 = faulttype-1)
22400
22500 ;back here after handliing fault
22600 DMOVE T1, SAVT1 ; restore regs
22700 DMOVE T3, SAVT3 ;
22800 DMOVE PN, SAVPN ;
22900 AOS SEMAFO ; reset semaphore
23000 JRSTF @FPC ; return to program
23100
23200 TABLE: JRST ACCESS ; access not allowed
23300 JRST GETIN ; page not in core
23400 JRST GETUUO ; UUO argument not in core
23500 JRST TIME ; time trap
23600 JRST CREATE ; zero page
23700 JRST CREATE ; UUO zero page
23800
23900
24000
24100 PAGE
24200 ;**********************************************************************
24300 ;
24400 ; INITIALISATION
24500 ;
24600 ;**********************************************************************
24700
24800 S$$PFZ: ; JSR here to initialise pfh
24900 0
25000
25100 ; Save regs
25200 DMOVEM T1, SAVT1
25300 DMOVEM T3, SAVT3
25400 DMOVEM PN, SAVPN
25500 MOVE P, STKWD ; set up stack
25600
25700 TRACE 0,<Initialising PFH>
25800
25900 IFE FTTEST<
26000 IFN FTSHOW< MESSAGE<Fasbol PFH setup>
26100 >>
26200
26300 ; set up the bit maps
26400
26500 ; first get the WS
26600 MOVE T1, [XWD .PAGWS, INMBLK]
26700 PAGE. T1, ; get WS
26800 INITE1: ERROR<INITE1> ; should never happen
26900
27000 ; now set up the others
27100 MOVEI T1, MAPSIZE-1 ; T1 is index into bitmap vectors
27200 INIT1: SETOM , ULTMAP(T1) ; set USEDLASTTIME map
27300 SOJGE T1, INIT1 ; and loop
27400 ; We mark all pages as USED-LAST-TIME so that they
27500 ; don't get shoved out during the first timeslice.
27600
27700 ; USEDTHISTIME map is set up when it is needed.
27800
27900 ; set up flags
28000 MOVEI T1, FFLSTA ; initial force level
28100 MOVEM T1, FORCFL ; initialise force level
28200 SETOM LASTPC ; LASTPC := nothing
28300 SETZM DMPADS ; not doing dump-mode IO
28400 SETZM SEMAFO ; initialise semaphore
28500
28600 ; ensure that I am in core before I take over from the system PFH.
28700 MOVEI T1, PFHSTR ; address of first word
28800 INITA: MOVE T2, (T1) ; access word - ensure that page is in core
28900 ADDI T1, PAGSIZ ; bump up address to point to next page
29000 CAIG T1, PFHEND ; all done?
29100 JRST INITA ; no - check next page
29200 MOVEI T1, PFHEND ; get end of loop right - check end addr is OK
29300 MOVE T2, (T1) ; access word
29400
29500 ; set up .JBPFH word in jobdat area to tell monitor we're here
29600 MOVE T1, [XWD PFHEND,PFHSTR]
29700 MOVEM T1, .JBPFH
29800
29900 ; remove old pfh from last 1K (if it is there)
30000 MOVE T1, [XWD .PAGCD, RPFLS1] ; set up call
30100 PAGE. T1, ; destroy page 776
30200 JRST [ ; error return
30300 TRACE T1, <Error code from 776>
30400 JRST INIT2
30500 ]
30600 INIT2: MOVE T1, [XWD .PAGCD, RPFLS2] ; set up call
30700 PAGE. T1, ; destroy page 777
30800 JRST [ ; error return
30900 TRACE T1, <Error code from 777>
31000 JRST INIT3
31100 ]
31200 INIT3:
31300
31400 ; set up incore map again - without old pfh
31500 PUSHJ P, REINIT
31600
31700 ; clear access bits for incore pages
31800 PUSHJ P, CLRABS
31900
32000 ; set up timing interval
32100 MOVEI T1, TIMINT ; get timing interval
32200 HRLI T1, 26 ; set up call of SETUUO
32300 SETUUO T1, ; set timing interval
32400 STERR: ERROR<STERR> ; oops!
32500
32600 DMOVE T1, SAVT1 ; restore regs
32700 DMOVE T3, SAVT3
32800 DMOVE P, SAVPN
32900 AOS SEMAFO ; restore semaphore
33000 JRSTF @S$$PFZ ; return to caller
33100
33200 ; end of INIT code
33300
33400
33500 PAGE
33600 ;************************************************************************
33700 ;
33800 ; REINIT
33900 ;
34000 ;************************************************************************
34100
34200 REINIT: ; subroutine
34300 ; Who's been eating my porridge ?
34400 ; Either the user or the monitor has altered the working set
34500 ; (the PF.HCB bit was set).
34600 ; This subroutine resets the INCORE bitmap
34700 ; nonskip return
34800
34900 TRACE 0,<WS changed - resetting>
35000
35100 MOVE T1, [XWD .PAGWS, INMBLK] ; set up call
35200 PAGE. T1, ; INMAP := working set
35300 REERR: ERROR<REERR> ; HELP!
35400 POPJ P, ; That's all folks!
35500
35600 ; end of subroutine REINIT
35700
35800
35900 PAGE
36000 ;*********************************************************************
36100 ;
36200 ; GETIN
36300 ;
36400 ;*********************************************************************
36500
36600 GETIN: ; subroutine to get a page into core
36700 ; page number in PN
36800 ; nonskip return
36900
37000 TRACE PN,<Fault on page>
37100
37200 PUSHJ P, OUTPAG ; start by shoving somebody out
37300 NOOP ; nobody got shoved out, but never mind
37400 ; we will try to increase the incore size
37500 GETIN1: MOVEI T4, 1 ; put in arg for PAGE UUO
37600 ; pageno is in PN
37700 ; requires that T4 and PN are consecutive regs
37800 MOVE T1, [XWD .PAGIO, T4] ; set up call
37900 PAGE. T1, ; get page into core
38000 JRST GETFC ; didn't suceed - force a page out
38100
38200 ; we have now got the page in - by fair means or foul
38300 TRACE PN,<In OK>
38400
38500 ; now set the bit in the INCORE map,
38600 PUSHJ P, MARKIN ;
38700
38800 ; allow access to the page
38900 JRST ACCESS ; and return direct to caller
39000
39100 GETFC: ; Here if we couldn't get the page in
39200 ; error code in T1
39300 PUSHJ P, FORCE ; force a page out
39400 JRST GETIN1 ; and try again
39500
39600
39700 ; end of subroutine GETIN
39800
39900
40000 PAGE
40100 ;**********************************************************************
40200 ;
40300 ; CREATE
40400 ;
40500 ;**********************************************************************
40600
40700 CREATE: ; Subroutine to create a new page
40800 ; pageno in PN
40900 ; nonskip return
41000
41100 TRACE PN,<Create page>
41200
41300 ; unlike GETIN we don't shove a page out first
41400 ; we assume that the user is growing.
41500 CREA1: MOVEI T4, 1 ; put in argument for PAGE UUO
41600 ; pageno is in PN
41700 ; requires that T4 and PN are consecutive regs
41800 MOVE T1, [XWD .PAGCD, T4] ; set up call
41900 PAGE. T1, ; create page in core
42000 JRST CFORC ; didn't succeed - force a page out
42100
42200 ; we have now created the page - by fair means or foul
42300 TRACE PN,<Created OK>
42400
42500 ; now set the bit in the INCORE map,
42600 ; we don't set access allowed, since he may be grabbing a large vector
42700 ; and he may not use it for a while.
42800 JRST MARKIN ; and return direct to caller
42900
43000
43100 CFORC: ; here if we weren't able to create a new page
43200 ; T1 contains error code from PAGE UUO.
43300
43400 ; find out what went wrong
43500 CAIN T1, PAGNS% ; no more swapping space ?
43600 JRST PFHNMS ; yes
43700 PUSHJ P, FORCE ; no - try forcing a page out
43800 ; T1 = error code
43900 JRST CREA1 ; try again
44000
44100 ; end of subroutine CREATE
44200
44300 PAGE
44400 ;****************************************************************************
44500 ;
44600 ; FORCE
44700 ;
44800 ;****************************************************************************
44900
45000 FORCE: ; subroutine to force pages out in order to get one in, or to
45100 ; create a new one.
45200 ; on entry T1 = error code from PAGE. UUO
45300 ; nonskip return
45400 TRACE 0,<Forcing>
45500
45600 CAIE T1, PAGLE% ; did we fail because of not enough
45700 ; physical core?
45800 FORCER: ERROR<FORCER> ; no - then shoving out pages won't help.
45900
46000 ; yes - shove out page and try again
46100
46200 FORC1: PUSHJ P, OUTPAG ; shove out a page
46300 SKIPA ; didn't succeed - continue
46400 POPJ P, ; page shoved out - return
46500
46600 ; there are no more candidate pages at this level of forcing
46700 ; try more brutal methods
46800 SOSL FORCFL ; reduce forcing level
46900 JRST FORC1 ; and loop unless it was already minimum
47000
47100 ; we are at the lowest level of forcing, and still we
47200 ; can't find a candidate page
47300 ; This user is just too small
47400 PUSHJ P, TOSMAL ; tell him the bad news
47500 ; if he continues, then he may have got more core
47600 ; so let the calling routine try again
47700 POPJ P,
47800
47900 ; end of subroutine FORCE
48000
48100 PAGE
48200 ;**********************************************************************
48300 ;
48400 ; TOSMAL
48500 ;
48600 ;*********************************************************************
48700
48800 TOSMAL: ; Subroutine called when user hasn't got enough physical core
48900 ; Normal return if user does a CONTINUE
49000
49100 PFHNEP: MESSAGE<?PFHNEP - NOT ENOUGH PHYSICAL CORE>
49200 HALT .+1 ; stop, and give him a chance to do
49300 ; something about it
49400 ; if he continues, then he may have got more core
49500 ; so return to caller
49600 POPJ P,
49700
49800 ; end of subroutine TOSMAL
49900
50000
50100 PAGE
50200 ;**********************************************************************
50300 ;
50400 ; PFHNMS
50500 ;
50600 ;**********************************************************************
50700
50800 PFHNMS: MESSAGE<?PFHNMS - NO MORE VM SWAPPING SPACE AVAILABLE>
50900 HALT . ; stop
51000
51100
51200 PAGE
51300 ;**********************************************************************
51400 ;
51500 ; MARKIN
51600 ;
51700 ;**********************************************************************
51800
51900 MARKIN: ; subroutine
52000 ; here if we have successfully got a page into core
52100 ; This subroutine marks the page in the INCORE map.
52200 ; nonskip return
52300
52400 MOVE T1, PN ; T1 := page number
52500 PUSHJ P, GETBIT ; T1 := index into bitmap, T2 := bit
52600 IORM T2, INMAP(T1) ; set bit in INCORE map
52700 POPJ P, ; return
52800
52900 ; end of subroutine MARKIN
53000
53100
53200 PAGE
53300 ;*************************************************************************
53400 ;
53500 ; ACCESS
53600 ;
53700 ;*************************************************************************
53800
53900 ACCESS: ; subroutine to allow access to a page
54000 ; PN = page number
54100 ; nonskip return
54200
54300 TRACE PN,<Allow access to page>
54400
54500 MOVEI T4, 1 ; put in arg for PAGE UUO
54600 ; PN is pageno
54700 ; requires that T4 and PN are consecutive regs
54800 MOVE T1, [XWD .PAGAA, T4] ; set up call
54900 PAGE. T1, ; allow acess to page
55000 ACERR: ERROR<ACERR> ; help!!
55100 POPJ P, ; all done
55200
55300 ; end of subroutine ACCESS
55400
55500
55600 PAGE
55700 ;************************************************************************
55800 ;
55900 ; OUTPAG and OUTPGN
56000 ;
56100 ;************************************************************************
56200
56300 ; Subroutines to shove a candidate page out
56400 ; OUTPAG has no parameters, and starts looking for a candidate
56500 ; at page 1
56600 ; OUTPGN starts looking at pageno in T1
56700 ; Skip return if OK, nonskip return if there were no candidates left.
56800 ; all regs smashed
56900
57000 OUTPAG: MOVEI T1, 1 ; OUTPAG starts looking at page 1
57100 OUTPGN: ; OUTPGN starts lookin at pageno in T1
57200 TRACE 0,<Shove someone out>
57300 MOVE T2, FORCFL ; param for FINPAG
57400 PUSHJ P, FINPAG ; find a candidate page
57500 POPJ P, ; no candidates - nonskip return
57600
57700 ; T1 contains the number of the page we are going to shove out
57800 TRACE T1,<Shove out page>
57900 MOVE T4, T1 ; T4 := pageno
58000 HRLI T4, 400000 ; set bit 0 (direction bit for PAGE UUO)
58100 MOVEI T3, 1 ; put in argument for PAGE UUO
58200 MOVE T2, [XWD .PAGIO, T3] ; set up call
58300 PAGE. T2, ; shove out page
58400 JRST OUTER ; didn't succeed - investigate
58500
58600 ; we have shoved the page out OK.
58700 ; T1 = pageno
58800 TRACE T1,<Shoved out OK>
58900 PUSHJ P, GETBIT ; T1 = index, T2 = bit
59000 ANDCAM T2, INMAP(T1) ; clear bit in INCORE map
59100 MOVEI T1, (T4) ; T1 := pageno
59200 JRST SKPRET ; return
59300
59400 OUTER: ; here if we couldn't shove the page out - PAGE UUO failed
59500 ; error code is in T2
59600 CAIN T2, PAGNS% ; VM swapping space used up?
59700 JRST PFHNMS ; yes
59800 CAIE T2, PAGSH% ; was the page in a sharable hiseg ?
59900 OUTER1: ERROR<OUTER1> ; no - then I don't know what to do
60000
60100 ; yes -the hiseg is sharable.
60200 ; Make note, so that we don't bother to look at it again
60300 TRACE 0,<Sharable Hiseg>
60400 MOVEI T1, 377 ; pageno of highest page in lowseg
60500 MOVEM T1, TOPPAG ; update TOPPAG
60600 POPJ P, ; no candidates - nonskip return
60700
60800 ; end of subroutine OUTPAG
60900
61000 PAGE
61100 ;**********************************************************************
61200 ;
61300 ; TIME
61400 ;
61500 ;**********************************************************************
61600
61700 TIME: ; Subroutine
61800 ; We come here at regular intervals, determined by a SETUUO
61900 ; at initialisation time.
62000 ; Do accouting.
62100 ; throw out all candidate pages which have not been used in
62200 ; this timeslice.
62300
62400 TRACE 0,<Time>
62500
62600 MOVEI T1, FFLSTA
62700 CAME T1, FORCFL ; were we forcing?
62800 JRST [ MOVEM T1, FORCFL ; yes - reset force level
62900 JRST TIM2 ; and don't shove more pages out
63000 ]
63100
63200 ; remove all candidate pages which haven't been shoved out yet
63300 MOVEI T1, 1 ; start looking at page 1
63400 TIM1: PUSHJ P, OUTPGN ; shove a page out
63500 SKIPA ; none left - break out of loop
63600 JRST TIM1 ; loop
63700
63800 TIM2: ; set up usedlasttime map
63900 ; USEDLASTTIME := USEDTHISTIME
64000 HRLI T1, UTTMAP
64100 HRRI T1, ULTMAP
64200 BLT T1, ULTMAP+MAPSIZE-1
64300
64400 ; clear access bits for incore pages
64500 JRST CLRABS ; (and return direct to caller)
64600
64700 ; end of subroutine TIME
64800
64900
65000 PAGE
65100 ;**********************************************************************
65200 ;
65300 ; CLRABS
65400 ;
65500 ;*********************************************************************
65600
65700 CLRABS: ; Subroutine to clear access bits for incore pages
65800 ; This means that we can find out which pages have been
65900 ; accessed during each time interval, and thus we can
66000 ; determine a (hopefully) sensible working set.
66100 ;
66200 ; We only clear access bits for potential candidates for
66300 ; shoving out.
66400 ;
66500 ; nonskip return
66600
66700 TRACE 0,<Clear access bits>
66800
66900 SETZM ALIST ; init alist count
67000
67100 MOVEI T1, 1 ; starting page for FINPAG
67200
67300 CLR1: MOVEI T2, 0 ; force level - INCORE
67400 PUSHJ P, FINPAG ; find a candidate page
67500 ; T1 = last page found
67600 ; T2 = 0 (force level)
67700 JRST CLR2 ; none left - exit
67800 ; T1 = pageno
67900 ; We put the page numbers in an array (ALIST) and clear
68000 ; them several at a time. This reduces the number of
68100 ; PAGE. UUOs.
68200 ; The zero'th element of ALIST contains the number of
68300 ; pagenos in the list.
68400 AOS T2, ALIST ; increment arglist index, and put it in T2
68500 MOVE T3, T1 ; T3 := pageno
68600 HRLI T3, 600000 ; set bit0 - clear access perm
68700 ; bit1 - automatic access allow (6.03)
68800 MOVEM T3, ALIST(T2) ; put arg in list
68900 CAIL T2, ALSIZE-1 ; is arglist full
69000 PUSHJ P, CLRALL ; yes - clear the pages we have so far
69100 AOJA T1, CLR1 ; loop for next page (T1 is still pageno)
69200
69300 CLR2: ; here when we are finished
69400 SKIPE ALIST ; unless arg list is empty
69500 PUSHJ P, CLRALL ; clear access for pages left in list
69600 POPJ P, ; return
69700
69800 ; end of subroutine CLRABS
69900
70000 PAGE
70100
70200
70300
70400 CLRALL: ; subroutine to clear the access bits for all the pages
70500 ; in ALIST in one go
70600 ; T1, T3 and T4 are not altered
70700 ; T2 is overwritten
70800 ; nonskip return
70900
71000 TRACE 0,<Clear list>
71100
71200 MOVE T2, [XWD .PAGAA, ALIST] ; set up call
71300 PAGE. T2, ; clear access bits
71400 CLERR: ERROR<CLERR> ; oops!
71500 SETZM ALIST ; zero index
71600 POPJ P, ; return
71700
71800 ; end of subroutine CLRALL
71900
72000
72100 PAGE
72200 ;*****************************************************************
72300 ;
72400 ; FINPAG
72500 ;
72600 ;*****************************************************************
72700
72800 FINPAG: ; subroutine to find a candidate page
72900 ; T1 = pageno to start looking at. This must be a valid pageno
73000 ; T2 = force level (see explanation below)
73100 ; we consider all pages between T1 and TOPPAG as candidates
73200 ; T1,T2,T3,T4 overwritten
73300 ; skip return if candidate is found - T1 = candidate
73400 ; nonskip return if no candidate found
73500
73600
73700 ; The force level has the following effect
73800 ; forcelevel = 0 - consider all incore pages as candidates
73900 ; forcelevel = 1 - consider all incore pages which haven't been
74000 ; accessed in the last time slot
74100 ; forcelevel = 2 - consider all incore pages which haven't been
74200 ; accessed in the last two time slots
74300 ;
74400 ; In any case we ignore pages which are not swapout possibilities
74500 ;
74600 ; page containing PC of fault
74700 ; PFH page(s) (if resident)
74800 ; DDT pages if we are debugging the PFH
74900 ; page containing APR trap word
75000 ; page(s) containing Interrupt vector
75100 ; page(s) containing PSI vectors
75200 ; page(s) to which the pfh iis doing dump-mode I/O
75300 ;
75400 ; The caller must ensure that we don't look at page zero (i.e. T1 gt 0)
75500 ; and that we don't look at page 777 for a VMX handler or a page in
75600 ; a sharable hiseg (i.e. TOPPAG sensible).
75700
75800 TRACE T1,<Find candidate>
75900
76000 DMOVEM T1, FPSTP ; save start and force level values
76100 IDIVI T1, 44 ; T1 := index into bitmap of start page
76200 MOVEM T1, FPINDX ; save it as well
76300 JRST FPAG2 ; skip over beginning of loop
76400
76500 FPAGL1: ; beginning of main loop
76600 ; here to find next word in bitmap
76700 ; T1,T2,T3,T4 unknown
76800 AOS T1, FPINDX ; increment index and put it into T1
76900
77000 FPAG2: ; T1 = index into bitmap
77100 ; T2,T3,T4 rubbish
77200 ; find a bitword of candidates
77300 MOVE T3, INMAP(T1) ; T3 := INCORE
77400 SKIPLE T2, FPLEV ; if forcelevel gt 0
77500 ANDCM T3, UTTMAP(T1) ; /\ NOT USED-THIS-TIME
77600 CAILE T2, 1 ; if forcelevel gt 1
77700 ANDCM T3, ULTMAP(T1) ; /\ NOT USED-LAST-TIME
77800
77900 FPAGL2: ; beginning of inner loop
78000 ; here to find next nonzero bit in bitword
78100 ; T3 = bitword
78200 ; T1,T2,T4, unknown
78300 JFFO T3, .+1 ; T3 unchanged, T4 := bitno of nonzero bit
78400
78500 ; The order of the following instructions is important
78600 ; If they are shuffled around the PFH may get into a loop.
78700
78800 ; calculate page number
78900 MOVE T1, FPINDX ; T1 := index into bitmap
79000 IMULI T1, 44 ; T1:= pageno of bit 0 of candidate word
79100 ADDI T1, (T4) ; T1:= pageno corresponding to nonzero bit
79200
79300 ; T1 = page number
79400 ; T3 = candidate bitword
79500 ; T4 = bit number
79600 ; T2 unknown
79700 CAMLE T1, TOPPAG ; pageno gt end?
79800 POPJ P, ; yes - end of loop - error return
79900
80000 JUMPE T3, FPAGL1 ; if candidate word is empty get next
80100 ; (This test must come after the
80200 ; test for end of loop)
80300
80400 ; remove bit from candidate word
80500 MOVNI T4, (T4) ; T4 := -bitno
80600 MOVEI T2, 1 ; T2 := bit35
80700 LSH T2, 43(T4) ; shift it left 35-bitno places
80800 ANDCM T3, T2 ; remove bit from candidate word
80900
81000 CAMGE T1, FPSTP ; is pageno gt startpage
81100 JRST FPAGL2 ; yes - go on to next candidate
81200 ; (This test is necessary because
81300 ; we start at the left hand end of the first word.
81400 ; It must come after removal of the bit
81500 ; from candidate word or we will loop forever.)
81600
81700 ; T1 = pageno
81800 ; 1 le T1 le TOPPAG le 777
81900 ; T3 = candidate bitword
82000 ; T2,T4 rubbish
82100
82200 ; now check if this page is special in some way
82300
82400 TRACE T1,<Candidate>
82500
82600 MOVE T2, FPC ; PC at page fault
82700 HRLI T2, (T2) ; T2 = [address,,address]
82800 PUSHJ P, BADPGS ; check if it is this page
82900
83000 ; is this page part of the PFH?
83100 MOVE T2, .JBPFH ; T2 := [last address,,first address]
83200 PUSHJ P, BADPGS ; check if this page is part of pfh?
83300
83400 IFN FTTEST<
83500 ; if we are debugging the pfh then don't shove DDT pages out
83600 SKIPN T2, .JBDDT ; is DDT alive? T2 := DDT addresses
83700 JRST FPAGT1 ; no - continue
83800 PUSHJ P, BADPGS ; check
83900 > ; end IFN FTTEST
84000
84100 FPAGT1: ; check for APR interrupt address
84200 SKIPN T2, .JBAPR ; APR trapping? T2 := APR trap address
84300 JRST FPAGT2 ; no - continue
84400 HRLI T2, (T2) ; T2 := [address,,address]
84500 PUSHJ P, BADPGS ; is this the APR page?
84600
84700 FPAGT2: ; check for the interrupt vector
84800 SKIPN T2, .JBINT ; Interrupt handling? T2 := interrupt vec adr.
84900 JRST FPAGT3 ; no - continue
85000 HRLI T2, (T2) ; copy address into Left half
85100 ADD T2, [3,,0] ; lh := address of highest word in vector
85200 PUSHJ P, BADPGS ; is this an interrupt vector page?
85300
85400 FPAGT3: ; check for PSI interrupt vectors
85500 SKIPN T2, PSIVEC ; user enabled for PSI interrupts?
85600 JRST FPAGT4 ; no - continue
85700 ; Format of T2 is
85800 ; bits 0-8 index of highest PSI block
85900 ; rh address of PSI vector
86000 LSH T2, -31 ; shift T2 25 places to the right
86100 ; T2 is now bits 0-10 of the PSIVEC value
86200 ; i.e. it is (index of highest PSI block)*4 (maybe +something)
86300 ; = offset of highest PSI block (they are 4 words long)
86400 ADDI T2, 3 ; offset of last word of last block
86500 ADD T2, PSIVEC ; address of last PSI word
86600 HRLI T2, (T2) ; into left half
86700 HRR T2, PSIVEC ; starting address into right half
86800 PUSHJ P, BADPGS ; does this page contain PSI interrupt block?
86900
87000 FPAGT4: ; Check whether this is a page to which the PFH
87100 ; is trying to do dump-mode IO
87200 SKIPN T2, DMPADS ; doing dump-mode IO for user?
87300 JRST FPAGT5 ; no - continue
87400 PUSHJ P, BADPGS ; check if this is in use
87500
87600 FPAGT5: ; EUREKA!!!
87700 TRACE T1,<Candidate found>
87800 JRST SKPRET ; success return
87900 ; T1 = pageno
88000
88100
88200 PAGE
88300
88400
88500
88600 BADPGS: ; dirty subroutine to check whether a page contains all or part
88700 ; of a vector.
88800 ; T1 = pageno
88900 ; T2 = [highest address of vector,,lowest address of vector]
89000 ; T2,T4 are overwritten
89100 ; T1,T3 preserved
89200 ; if page contains all or part of vector we pop the return address
89300 ; off the stack and jump direct to FPAGL2
89400 ; nonskip return otherwise
89500
89600 LDB T4, [POINT 9,T2,26] ; pageno of lowest address
89700 LSH T2, -33 ; pageno of highest address
89800 CAIG T1, (T2) ; if T1 gt highest pageno
89900 CAIGE T1, (T4) ; or if T1 lt lowest pageno
90000 POPJ P, ; then we are OK
90100 ; no good - lowest page le T1 le highest
90200 POP P, T4 ; remove return address from stack
90300 JRST FPAGL2 ; and try next candidate
90400
90500 ; end of subroutine BADPGS
90600
90700 ; end of subroutine FINPAG
90800
90900
91000 PAGE
91100 ;******************************************************************
91200 ;
91300 ; GETUUO
91400 ;
91500 ;******************************************************************
91600
91700 GETUUO: ; Subroutine to get a UUO argument into core
91800 ; PN = Page number
91900 ;
92000 ; The subroutine checks whether the user program has
92100 ; got into a page fault loop trying to do dump-mode I/O
92200 ; to more core than his physical allowance.
92300 ; In this case the pfh simulates the I/O a page at a time.
92400
92500 TRACE PN,<Fault on page for UUO>
92600
92700 MOVE T1, FPC ; PC for this fault
92800 CAMN T1, LASTPC ; same as PC for previous fault ?
92900 JRST GUUO1 ; yes
93000
93100 ; no - we are not in a page fault loop
93200 MOVEM T1, LASTPC ; remember this PC for next time
93300 MOVEI T1, 30
93400 MOVEM T1, LPCCT ; reset counter
93500 JRST GETIN ; get the page in
93600 ; (and return direct to caller)
93700
93800 GUUO1: SOSLE T2, LPCCT ; have the last 24 faults all been from
93900 ; the same PC?
94000 JRST GETIN ; no - get page (and return direct to caller)
94100 JUMPN T2, GUUO2 ; yes - is this the 24'th fault?
94200 PUSHJ P, CHKIOD ; yes - is it a dump-mode I/O instruction?
94300 JRST SIMDMP ; yes - go and simulate I/O for user
94400 ; (return direct to caller)
94500 GUUO2: ; no - the last 24 (or more) faults have all been from the same PC
94600 ; but it isn't a dump-mode I/O instruction. (Or it is not
94700 ; one which we feel confident to simulate.)
94800 ; It is conceivable that he isn't actually in a loop
94900 ; in which case we don't want to kill his program
95000 ; so we let him continue until we are absolutely certain.
95100 CAMGE T2, [-140] ; have the last 100 page faults all been
95200 ; from the same PC
95300 PUSHJ P, TOSMAL ; yes - tell him he is too small
95400 ; if he continues he may have got more core
95500 JRST GETIN ; keep trying - get the page in
95600 ; (and return direct to caller)
95700
95800 ; end of subroutine GETUUO
95900
96000
96100 PAGE
96200 ;***************************************************************************
96300 ;
96400 ; CHKIOD
96500 ;
96600 ;***************************************************************************
96700
96800 CHKIOD: ; Subroutine to check whether the user program is trying to
96900 ; do a dump-mode I/O instruction
97000 ; on entry T1 = PC
97100 ; Nonskip return if the user is doing dump-mode i/o to a "nice" device
97200 ; with T2 = instruction
97300 ; Skip return if not dump-mode I/O
97400 ; In either case T1,T2,T3,T4 destroyed.
97500 ;
97600 ; The criterion for a "nice" device is that it can do
97700 ; dump-mode I/O 1000 (octal) words at a time.
97800 ; Devices allowed are disk, dectape
97900 ; magtape is allowed for record dump i/o only
98000
98100 PUSHJ P, GETINS ; get instruction word
98200 ; T2 = instruction, T3 = opcode
98300 CAIE T3, 56 ; is it IN ?
98400 CAIN T3, 57 ; or OUT ?
98500 JRST CHD1 ; yes
98600 CAIE T3, 66 ; is it INPUT ?
98700 CAIN T3, 67 ; or OUTPUT ?
98800 JRST CHD1 ; yes
98900 JRST SKPRET ; no - not an I/O instruction - skip return
99000
99100 CHD1: ; The instruction is an I/O instruction
99200 LDB T4, [POINT 4,T2,12] ; T4 := channel number
99300 MOVE T3, [GETSTS 0, T1] ; inst we will XCT
99400 DPB T4,[POINT 4,T3,12] ; put chan no in XCT word for GETSTS
99500 XCT T3 ; Do a GETSTS, T1 := status
99600 ANDI T1, 17 ; T1 := mode
99700 CAIGE T1, 16 ; dump mode ? (16 or 17)
99800 JRST SKPRET ; no - skip return
99900 DEVCHR T4, ; get characteristics
00100 TLNE T4, 200100 ; is this a "nice" device ?
00200 ; disc
00300 ; dectape
00400 POPJ P, ; yes - nonskip return
00500 TLNE T4, 000020 ; is it a magtape ?
00600 CAIE T1, 16 ; and is data mode record dump ?
00700 JRST SKPRET ; no - skip return
00800 POPJ P, ; yes - nonskip return
00900
01000 ; end of subroutine CHKIOD
01100
01200 PAGE
01300 ;*************************************************************************
01400 ;
01500 ; SIMDMP
01600 ;
01700 ;*************************************************************************
01800
01900 SIMDMP: ; Subroutine to simulate dump-mode I/O for user
02000 ; We split up his I/O command list, and do it 1 page at a time.
02100 ; On entry T2 = instruction
02200
02300 TRACE 0,<Simulating Dump mode IO>
02400
02500 LDB T1, [POINT 13,T2,12] ; get opcode and channel
02600 DPB T1, [POINT 13,MYIOIN,12] ; set up I/O instruction for XCT
02700 PUSHJ P, GETEA ; T1 := effective address
02800
02900 SIMDL1: ; Beginning of main loop
03000 ; T1 = address of command list entry
03100 PUSHJ P, GETWD ; T2 := command list entry
03200 JUMPE T2, SIMEND ; all finished ?
03300 JUMPL T2, SIMDL2 ; is this an IOWD or a GOTO?
03400 MOVEI T1, (T2) ; it is a GOTO T1 := address
03500 JRST SIMDL1 ; loop
03600
03700 SIMDL2: ; Beginning of inner loop
03800 ; Here when T2 is a genuine IOWD
03900 ; T2 = -LEN,,ADR
04000 DMOVEM T1, SIMSVR ; save T1,T2
04100 HLRE T1, T2 ; T1 := -LEN
04200 CAMG T1, [-PAGSIZ] ; LEN gt 1000 ?
04300 MOVNI T1, PAGSIZ ; yes - transfer 1 page only
04400 HRLI T2, (T1) ; new -LEN into T2
04500 MOVEM T2, MYIOWD ; set up I/O instruction
04600
04700 ; now get the page(s) addressed by my IOWD into core
04800 SETCA T1, ; T1 := LEN-1
04900 ADDI T1, (T2) ; T1 := highest address referenced
05000 HRLM T1, DMPADS ; put it in LH of DMPADS
05100 HRRM T2, DMPADS ; lowest address in RH
05200 ; tells FINPAG not to shove these pages out
05300 PUSHJ P, GETWD ; make sure highest address page is in core
05400 HRR T1, DMPADS ; lowest address
05500 PUSHJ P, GETWD ; make sure page is in core
05600 DMOVE T1, SIMSVR ; restore T1=address, T2=IOWD
05700
05800 ; now do the partial IO
05900 XCT MYIOIN ; do it
06000 SKIPA ; nonskip return - continue
06100 JRST SIMDME ; skip return - error
06200 ADD T2, [PAGSIZ,,PAGSIZ] ; increment IOWD
06300 JUMPL T2, SIMDL2 ; if there is still something to do
06400 ; then loop
06500
06600 ; we are finished with this IOWD
06700 AOJA T1, SIMDL1 ; go on to next word in command list
06800
06900
07000 SIMDME: ; here if we got an error return from the I/O instruction
07100 AOS FPC ; pass on skip return to user prog
07200
07300 SIMEND: ; here when we are finished simulating the I/O
07400 AOS T1, FPC ; return to user PC +1
07500 SETZM DMPADS ; tell FINPAG we are finished
07600 PUSHJ P, GETINS ; get the instruction
07700 ; This ensures that we don't get a
07800 ; pagefault when we try to return
07900 ; to the user prog
08000 POPJ P, ; all done
08100
08200 ; end of subroutine SIMDMP
08300
08400
08500 PAGE
08600 ;*******************************************************************
08700 ;
08800 ; GETWD
08900 ;
09000 ;*******************************************************************
09100
09200 GETWD: ; Subroutine to get the contents of an address
09300 ; It checks whether the address is one of the regs we
09400 ; have saved, and ensures that the page is in core
09500 ; on entry T1 = address
09600 ; nonskip return with T1= address, T2 = contents
09700 ; T3,T4 destroyed
09800
09900 CAIL T1, T1 ; is this one of the regs we have saved ?
10000 CAILE T1, P ;
10100 JRST GETWD1 ; no - continue
10200
10300 MOVE T2, SAVT1-1(T1) ; yes - get saved value
10400 POPJ P, ; and return
10500
10600 GETWD1: PUSH P, PN ; save PN
10700 PUSH P, T1 ; save address
10800 LSH T1, -11 ; pageno into T1
10900 MOVEI PN, (T1) ; and PN
11000 HRLI T1, .PAGCA ; set up call of PAGE. UUO
11100 PAGE. T1, ; get access bits for page
11200 GEWER: ERROR<GEWER> ; oops!
11300 TLNE T1, 020000 ; is it allocated but zero?
11400 JRST [ PUSHJ P, CREATE ; yes - create it in core
11500 JRST GETWD2 ] ; and allow access
11600 TLNE T1, 004000 ; is it paged out?
11700 JRST [ PUSHJ P, GETIN ; yes - get it in
11800 JRST GETWD3 ] ; and carry on
11900 TLNN T1, 040000 ; is access allowed?
12000 GETWD2: PUSHJ P, ACCESS ; no - allow it
12100
12200 GETWD3: ; here when the page is in core and accessible
12300 POP P, T1 ; T1 := address
12400 MOVE T2, (T1) ; contents
12500 POP P, PN ; restore PN
12600 POPJ P, ; return
12700
12800 ; end of subroutine GETWRD
12900
13000
13100 PAGE
13200 ;*********************************************************************
13300 ;
13400 ; GETEA
13500 ;
13600 ;*********************************************************************
13700
13800 GETEA: ; subroutine to calculate the effective address of an instruction
13900 ; on input T2 = inst, which can contain indirection bit and acc field
14000 ; nonskip return
14100 ; T1 = effective address
14200 ; T2,T3,T4 smashed
14300
14400 LDB T1, [POINT 4,T2,17] ; get acc field
14500 JUMPE T1, GETEA1 ; unless it is zero
14600
14700 PUSH P, T2 ; save instruction
14800 PUSHJ P, GETWD ; T2 := contents of acc
14900 POP P, T1 ; T1 := instruction
15000 ADDI T2, (T1) ; add address field to accumulator contents
15100 HLL T2, T1 ; T2 is instruction with new address part
15200
15300 GETEA1: TLNN T2, 000020 ; indirection bit set ?
15400 JRST GETEA2 ; no - continue
15500 MOVEI T1, (T2) ; get adr
15600 PUSHJ P, GETWD ; T2 := contents
15700 JRST GETEA ; and loop
15800
15900 GETEA2: ; all done - RH of T2 contains effective address
16000 MOVEI T1, (T2) ; T1 := EA
16100 POPJ P, ; return
16200
16300 ; end of subroutine GETEA
16400
16500 PAGE
16600 ;**************************************************************************
16700 ;
16800 ; GETINS
16900 ;
17000 ;**************************************************************************
17100
17200 GETINS: ; Subroutine to get an instruction
17300 ; It unwinds an XCT instruction
17400
17500 ; on entry T1 = PC
17600 ; nonskip return
17700 ; T2 = instruction
17800 ; T3 = opcode
17900
18000 PUSHJ P, GETWD ; T2 := instruction
18100 LDB T3, [POINT 9,T2,8] ; T3 := opcode
18200 CAIE T3, 256 ; is it an XCT ?
18300 POPJ P, ; no - all done
18400 PUSHJ P, GETEA ; T1 := effective address
18500 JRST GETINS ; and loop
18600
18700 ; end of subroutine GETINS
18800
18900 PAGE
19000
19100 ;******************************************************************
19200 ;
19300 ; GETBIT
19400 ;
19500 ;******************************************************************
19600
19700 GETBIT: ; subroutine to calculate the index into the bitmap
19800 ; and the bit corresponding to a page number.
19900 ; page number in T1
20000 ; on return T1 is index, T2 is bit
20100 ; T3 overwritten, T4 preserved
20200 ; nonskip return
20300
20400 IDIVI T1, 44 ; bit number in T2, index in T1
20500 MOVN T3, T2 ; negative shift count into T3
20600 MOVEI T2, 1 ; T2 := bit35
20700 LSH T2, 43(T3) ; shift bit left (35-bitnumber) places
20800 POPJ P, ; return
20900
21000 ; end of subroutine GETBIT
21100
21200
21300 PAGE
21400 ;******************************************************************
21500 ;
21600 ; SKPRET
21700 ;
21800 ;******************************************************************
21900
22000 SKPRET: ; JRST SKPRET is the same as doing a skip return
22100
22200 AOS (P) ; set up skip return
22300 POPJ P, ; do it
22400
22500 ; end of SKPRET
22600
22700
22800 PAGE
22900 ;*****************************************************************
23000 ;
23100 ; OUTNUM
23200 ;
23300 ;*****************************************************************
23400
23500 IFN FTTEST<
23600
23700 OUTNUM: ; subroutine used by the TRACE macro to print a number on the TTY
23800 ; argument is in T1
23900 ; it is printed in the form "LH,,RH - "
24000 ; nonskip return
24100 ; no regs are altered (not even T1)
24200
24300 PUSH P, T1 ; save T1
24400 HLRZ T1, T1 ; get left half of argument
24500 PUSHJ P, POCT ; print it
24600 OUTSTR [ASCIZ/,,/] ; make output pretty
24700 HRRZ T1, (P) ; get right half of argument from
24800 ; where we stored it on the stack
24900 PUSHJ P, POCT ; print it
25000 OUTSTR [ASCIZ/ - /] ; more pretty-print
25100 POP P, T1 ; restore T1
25200 POPJ P, ; return
25300
25400 ; end of subroutine OUTNUM
25500
25600
25700 POCT: ; subroutine to print an 18-bit octal number
25800 ; argument is in T1
25900 ; T1 is destroyed, but no other regs are altered
26000 ; nonskip return
26100
26200 PUSH P, T2 ; save T2
26300 IDIVI T1, 10 ; T1 := T1/8 ; T2 := T1 modulo 8
26400 SKIPE ,T1 ; any leading digits
26500 PUSHJ P, POCT ; yes - print them recursively
26600 ADDI T2, "0" ; convert digit to ascii
26700 OUTCHR T2 ; print it
26800 POP P, T2 ; restore T2
26900 POPJ P, ; return
27000
27100 ; end of subroutine POCT
27200
27300
27400 > ;end of IFN FTTEST
27500
27600
27700 PAGE
27800 ;****************************************************************
27900 ;
28000 ; DATA AREA
28100 ;
28200 ;****************************************************************
28300
28400 SAVT1: BLOCK 2 ; register save area
28500 SAVT3: BLOCK 2
28600 SAVPN: BLOCK 2
28700
28800 FORCFL: BLOCK 1 ; current forcing level
28900 SEMAFO: EXP 1 ; semaphore
29000 LASTPC: BLOCK 1 ; PC of last page fault - to check for loops
29100 LPCCT: BLOCK 1 ; Number of times we have pagefaulted at the same PC
29200 DMPADS: BLOCK 1 ; points to pages involved in dump I/O
29300
29400 FPSTP: BLOCK 1 ; private variables for FPAG
29500 FPLEV: BLOCK 1 ; FPLEV must come immediately after FPSTP
29600 FPINDX: BLOCK 1
29700
29800 MYIOIN: IN 0, MYIOWD ; IO instruction we will XCT for dump-mode IO
29900 MYIOWD: BLOCK 1 ; IO command list
30000 EXP 0 ; end of IO command list
30100
30200 SIMSVR: BLOCK 2
30300
30400 TOPPAG: EXP 777 ; highest possible candidate page no
30500 STKWD: IOWD STKSIZ,STACK
30600 STACK: BLOCK STKSIZ
30700
30800 UTMBLK: EXP MAPSIZE
30900 UTTMAP: BLOCK MAPSIZE ; pages used in this time slice
31000 ULTMAP: BLOCK MAPSIZE ; pages used in last time slice
31100 INMBLK: EXP MAPSIZE
31200 INMAP: BLOCK MAPSIZE ; pages currently in core (working set)
31300
31400 ALIST: BLOCK ALSIZE+1 ; arglist for CLRABS
31500 RPFLS1: EXP 1 ; arglist used for removing old pfh
31600 EXP 400000000776
31700 RPFLS2: EXP 1
31800 EXP 400000000777
31900
32000 IFN FTTEST<
32100 ERMST: ASCIZ/?PFHERR - PFH ERROR: /
32200 >
32300 PAGE
32400 LIT
32500 PAGE
32600 PFHEND=.+1
32700
32800 > ; IFN P$VM
32900
33000 END
33100
33200