Trailing-Edge
-
PDP-10 Archives
-
cuspjul86upd_bb-jf24a-bb
-
10,7/galaxy/glxlib/glxmem.mac
There are 26 other files named glxmem.mac in the archive. Click here to see a list.
TITLE GLXMEM -- Memory Manager for GALAXY Programs
SUBTTL Chuck O'Toole & Irwin L. Goverman/CDO/ILG/MLB/DC/PJT/DPM/TARL 5-Feb-85
;
;
; COPYRIGHT (c) 1975,1976,1977,1978,1979,1980,1981,1982,
; 1983,1984,1985,1986
; DIGITAL EQUIPMENT CORPORATION
; ALL RIGHTS RESERVED.
;
; THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED
; AND COPIED ONLY IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE
; AND WITH THE INCLUSION OF THE ABOVE COPYRIGHT NOTICE. THIS
; SOFTWARE OR ANY OTHER COPIES THEREOF MAY NOT BE PROVIDED OR
; OTHERWISE MADE AVAILABLE TO ANY OTHER PERSON. NO TITLE TO
; AND OWNERSHIP OF THE SOFTWARE IS HEREBY TRANSFERRED.
;
; THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE
; WITHOUT NOTICE AND SHOULD NOT BE CONSTRUED AS A COMMITMENT
; BY DIGITAL EQUIPMENT CORPORATION.
;
; DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR RELIABILITY
; OF ITS SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY
; DIGITAL.
SEARCH GLXMAC ;SUBSYSTEMS SYMBOLS
PROLOG(GLXMEM,MEM) ;PRODUCE PROLOG CODE
MEMEDT==31 ;MODULE EDIT LEVEL
SUBTTL Entry Points found in GLXMEM
ENTRY M%INIT ;Initialization entry point
ENTRY M%ACQP ;Acquire a page from the page map (page number is returned)
ENTRY M%RELP ;Return page to the page map (by page number)
ENTRY M%GPAG ;Get a free page (address is returned)
ENTRY M%RPAG ;Return a page to the page map (by address)
ENTRY M%IPSN ;Notification that IPCF send of page is about to occur
ENTRY M%NXPG ;Get a non-existant page for an IPCF receive
ENTRY M%IPRC ;Notification that IPCF receive of a page has occurred
ENTRY M%IPRM ;Make room for IPCF page we couldn't fit in core
ENTRY M%AQNP ;Acquire N contiguous pages from the map
ENTRY M%RLNP ;Release pages acquired from M%AQNP
ENTRY M%CLNC ;Clean Core For Cusps About To Go Dormant
ENTRY M%FPGS ;Return free page counter
ENTRY M%GMEM ;Allocate a chunk of memory
ENTRY M%RMEM ;De-allocate a chunk of memory
ENTRY PAGFRE ;Called from I%INIT
SUBTTL Table of contents
; TABLE OF CONTENTS FOR GLXMEM
;
;
; SECTION PAGE
; 1. Entry Points found in GLXMEM.............................. 2
; 2. Table of contents......................................... 3
; 3. Revision History.......................................... 4
; 4. Global Storage............................................ 5
; 5. M%INIT - Initialize the memory system..................... 6
; 6. PAGFRE - Determine if a given page is free or not......... 7
; 7. M%GPAG - Acquire one free page full of zeroes (address)... 8
; 8. M%ACQP - Acquire one free page full of zeroes (page number) 8
; 9. M%AQNP - Acquire several free pages full of zeroes........ 9
; 10. FNDPAG - Find first free page............................. 9
; 11. CREPAG - Routine to create a page......................... 10
; 12. M%NXPG - Acquire the number of a free page for IPCF reception 11
; 13. M%RLNP - Release contiquous free pages.................... 12
; 14. M%RELP - Release a single page to the free pool (by page number) 12
; 15. M%RPAG - Release a single page to the free pool (by address) 12
; 16. M%FPGS - Return number of free pages...................... 12
; 17. M%IPSN - Inform that page is about to be sent via IPCF.... 13
; 18. M%IPRC - Inform that page has been created via IPCF....... 13
; 19. M%GMEM - Allocate a chunk of memory....................... 14
; 20. APMEM - Routine to add one page to the chunk pool........ 15
; 21. PGCOLL - Routine to remove whole pages from chunk free pool 16
; 22. M%RMEM - Routine to de-allocate a memory chunk............ 17
; 23. Consistency checking routines............................. 18
; 24. M%CLNC - Routines for cleaning up core.................... 19
; 25. M%IPRM - Routine to swap out anything possible............ 20
; 27. TOPS-20 Dummy routines.................................... 22
SUBTTL Revision History
COMMENT \
Edit SPR/QAR Explanation
---- ------- -----------------------------------------------------
0001 First pass at GLXMEM, remove AP usage, etc.
0002 Remove TOPS-10 PFH and move it to the GLXINI module
0003 Convert to new OTS format
0004 Move creation of data area to INIT module
0005 Add M%GPAG and M%RPAG
0006 G053 Fix M%NXPG on the -20 to clear PT.USE and PT.WRK
0007 G054 Fix GMEM and RMEM to Garbage Collected when asked for
more than CNK.PM pages and cleanup core when available
pages exceeds PAGAVL
0010 Make BPN $STOP dump out offending page number
0011 Remove usage of PJUMPE opdef
0012 Arrange to zero our own $DATA space, but keep the stuff
we need for restart. Also, comment out the zeroing of any
location that gets zeroed on initialization.
0013 On TOPS20, make M%INIT start scanning for free pages
at c(.JBFF), not page zero.
0014 Restructure GLXLIB
1) Do PFH initialization here instead of in PFH. This includes
mapping core and marking all symbol table pages.
2) Create a non-sharable page and BLT the PFH into it.
3) As part of PFH setup, add new routine PFHADR to tell the
page fault handler where some of the memory manager data
base lives.
4) Add PFHRET kludge to allow the page fault handler to return
to the library when execute-only is in effect.
5) Copy NODDT routine here from PFH.
0015 Add new bit IB.NPF in the IB to disable GLXPFH.
0016 Shuffle some variables so GLXPFH can keep its data base in
core. This is needed to avoid the possibility of getting a
fault in the PFH itself. Also, force PFHRET whether or not
GLXLIB is execute only.
0017 Shift some stuff around to preserve which locations get
zeroed on a re-start. Broken by edit 16.
0020 Fix Stevens QAR on memory management loop. Allow calls to
M%GMEM of greater then CNK.PM*PAGSIZ words.
0021 Synchronize with edit 15 to GLXPFH. Remove interface from
GLXPFH to GLXMEM.
0022 Make creating PFH more robust. Don't call CREPAG to create
page for PFH, do our own PAGE. uuo. If fails because of
physical limit, swap out page 1, create ours, then swap 1
back in.
0023 Remove GLXPFH. Set PHY core limit low and request a timer
trap to invoke the system PFH.
0024 Clean and simplify M%IPRM. Allow it to give error returns.
0025 Remove reference to obsolete PFH symbols, and fix problem
with M%CLNC not being called enough to kill pages.
0026 Don't set guigelines since PFH will work without doing that.
0027 Dont reset PT.ADR when restarting so GLXMEM doesnt stopcode.
0030 In M%IPRM, make sure we clear PT.USE for the page just
destroyed. We only used it to make a hole in core.
26-Oct-84 GCO 10109 /LWS
0031 In CREPAG, don't trust the VTRPRV flag. It only reflects the
IB.NPF bit, not real virtual privs. Try to make virtual pages,
and only give up if we can't.
5-Feb-85 GCO ????? /RCB
\
SUBTTL Global Storage
$GDATA VRTPRV ;VIRTUAL PRIVS FLAG (0 = NONE, 1 = YES)
$GDATA PAGTBL,MEMSIZ ;PAGE MAP OF ALL PAGES
$DATA PAGSTA ;STARTING POINT FOR PAGSRC PAGES
$DATA MEMBEG,0 ;START OF ZEROABLE DATA FOR GLXMEM
$DATA AVBPGS ;COUNT OF RELP'D BUT IN CORE PAGES
$DATA FREPGS ;COUNT OF FREE PAGES IN ADR SPACE
$DATA FREWDS ;FREINI, EXPRESSED AS WORDS NOT PAGES
$DATA DICT,DCT.MX+1 ;CHUNK DICTIONARY OF FREQUENTLY USED SIZES
$DATA PANFLG ;FLAG FOR CHUNK MANAGER
$DATA APCNT ;COUNTER FOR COLLECT OR ADD PAGE TEST
$DATA CNT.AP ;COUNTER: PAGES ADDED TO FREE CHUNK POOL
$DATA CNT.DD ;COUNTER: TIMES DICT HAD TO BE DUMPED
$DATA CNT.PC ;COUNTER: NUMBER OF PAGES GARBAGE COLLECTED
$DATA CNT.CL ;COUNTER: TIMES RECLAIMED MEMORY
$DATA MEMEND,0 ;END OF ZEROABLE DATA FOR GLXMEM
;HERE COMES NON-ZEROABLE $DATA SPACE
$DATA MEMFLG ;-1 WHEN M%INIT HAS BEEN CALLED
$DATA FREINI ;INITIAL VALUE OF FREPGS FOR CHECKING
SUBTTL M%INIT - Initialize the memory system
; M%INIT HAS THE TASK OF PUTTING THE PAGE TABLE AND PAGE COUNTERS INTO
; A DETERMINED STATE.
; CALL IS: NO ARGUMENTS
;
;TRUE RETURN: ALWAYS
M%INIT: MOVE S1,[MEMBEG,,MEMBEG+1] ;SETUP BLT PTR TO ZERO $DATA SPACE
SETZM MEMBEG ;ZERO OUT FIRST LOCATION
BLT S1,MEMEND-1 ;AND DO THE REST
SKIPGE MEMFLG ;HAVE WE BEEN HERE BEFORE (RESTART)?
JRST INIT.3 ;YES, RESTORE INITIAL STATE
SETOM MEMFLG ;NO, DETERMINE INITIAL STATE
TOPS10 <MOVEI S1,0> ;START AT PAGE 0
TOPS20 <HRRZ S1,.JBFF##> ;START FROM FIRST FREE
ADR2PG S1 ;CONVERT TO PAGE NUMBER
SETOM PAGSTA ;NO PAGE MARKED AS FIRST FREE YET
INIT.1: PUSHJ P,PAGFRE ;IS THIS PAGE FREE?
JUMPN S2,INIT.2 ;IF ITS IN USE, MARK IT AS SUCH
AOS FREINI ;INCREMENT COUNT OF FREE PAGES
SKIPGE PAGSTA ;HAVE WE ALREADY FOUND ONE FREE PAGE?
MOVEM S1,PAGSTA ;NO, SO SET IT UP NOW
INIT.2: STORE S2,PAGTBL(S1),PT.INI ;SAVE INITIAL BIT (1=PART OF ORIGINAL)
STORE S2,PAGTBL(S1),PT.USE ;SET THE PAGE STATUS UP TOO
STORE S2,PAGTBL(S1),PT.ADR ;AND ADDRESSABLE
CAIE S1,MEMSIZ-1 ;LOOP FOR ALL PAGES
AOJA S1,INIT.1 ;MARKING FREE AND INUSE
JRST INIT.6 ;THEN DO COMMON SET UP
INIT.3: MOVEI S1,0 ;START AT PAGE 0
INIT.4: LOAD S2,PAGTBL(S1),PT.INI ;GET INITIAL IN-USE BIT
STORE S2,PAGTBL(S1),PT.USE ;RESET 'IN USE' BIT FOR THIS PAGE
CAIE S1,MEMSIZ-1 ;ARE WE DONE?
AOJA S1,INIT.4 ;NO, SO DO NEXT PAGE
INIT.6: MOVE S1,FREINI ;GET NUMBER OF FREE PAGES
MOVEM S1,FREPGS ;STORE CURRENT NUMBER OF FREE PAGES
PG2ADR S1 ;CONVERT TO WORDS
MOVEM S1,FREWDS ;AND STORE THAT TOO
MOVX S1,DDCNT ;RE-SET THE DICT DUMP COUNT
MOVEM S1,APCNT ;FOR M%GMEM AND M%RMEM
PUSHJ P,M%CLNC ;CLEAN UP CORE
ZERO AVBPGS ;CLEAR COUNT OF AVAILABLE PAGES
PUSHJ P,PFHINI ;SET UP THE PAGE FAULT HANDLER
$RETT ;ALL DONE, RETURN NOW
SUBTTL System PFH interface
; System page fault handler (PFH) initialization
;
PFHINI: SETZM VRTPRV ;ASSUME NO VIRTUAL PRIVS
TOPS10 < ;TOPS-10 ONLY
MOVX TF,IB.NPF ;GET 'DON'T SET UP GLXPFH' BIT
SKIPN .JBPFH ;ALREADY SET UP?
TDNE TF,IIB##+IB.FLG ;USER WANT PFH ?
POPJ P, ;NO - JUST RETURN
HRROI TF,.GTMVL ;SET UP AC
GETTAB TF, ;READ MAXIMUM CORE LIMITS
SETZ TF, ;CAN'T
TLNN TF,-1 ;HAVE VM PRIVS ?
POPJ P, ;NOPE - JUST RETURN
AOS VRTPRV ;YES - REMEMBER IT
PFHI.1: MOVE S2,[.STTVM,,^D1000] ;REQUEST A VIRTUAL TIMER TRAP
SETUUO S2, ;AFTER 1000 MILLISECONDS
JFCL ;LOSER
POPJ P, ;RETURN
> ;END OF TOPS10 CONDITIONAL
TOPS20 < ;TOPS-20 ONLY
AOS VRTPRV ;ALWAYS HAVE VIRTUAL PRIVS ON THE -20
POPJ P, ;RETURN
> ;END OF TOPS-20 CONDITIONAL
SUBTTL NODDT - Remove DDT.VMX routine for TOPS10
TOPS10 < ;TOPS-10 ONLY
;This routine is intended to be used as an emergency tool
; in case a library gets saved with DDT in its high segment.
; In this case, any lowseg program which also has DDT.VMX in page 700
; will get page overlap errors when getting the library.
; It is not the intention that the library be saved in this state,
; however, if it happens, then this routine will be useful.
; The procedure is as follows:
; .GET GLXLIB ;The bad one, with DDT.VMX in it
; .DDT ;get into DDT.VMX
; NODDT$G ;Start it at this routine
; .SAVE ;Save the library without the symbols
;
;This routine is also useful to remove VMDDT after a component
;has been attached to, and DDTed. It will remove VMDDT and continue
;the program at .JBOPC (the interrupted PC)
;
; NODDT$G ;Remove VMDDT and restart @.JBOPC
NODDT:: SKIPN S1,DDTADR ;Get the end,,start adr of DDT
JRST NODD.2 ;No DDT to begin with!
HRRZ T2,S1 ;Get start adr of DDT
HLRZ P1,S1 ;And ending adr
ADR2PG T2 ;Make starting page number
ADR2PG P1 ;Make ending page number
SUB P1,T2 ;Get number of pages in DDT
TXO T2,1B0 ;Light the destroy page bit
MOVEI T1,1 ;Count the args to PAGE. UUO
MOVE S2,[XWD .PAGCD,T1] ;Create/Destroy,, adr of arg list
NODD.1: PAGE. S2, ;Get rid of a page
JRST NODDFA ;Complain!
AOS T2 ;Bump to next page
SOJGE P1,NODD.1 ;And try the rest of the pages
SETZ S1, ;Store 0 in protected DDT loc
SETDDT S1, ;And tell the monitor
NODDTE: SKIPN .JBOPC ;Old PC around?
EXIT ;No--Just exit
JRSTF @.JBOPC ;Yes--Resume program
;Here is trying to destroy DDT, and it isn't here at all!
NODD.2: OUTSTR [ASCIZ/
% DDT not loaded
/] ;Inform the dumb user
JRST NODDTE ;And leave 'em alone
;Here if the PAGE. UUO fails
NODDFA: OUTSTR [ASCIZ/
?Can't destroy DDT page
/]
JRST NODDTE ;And die
> ;End of TOPS-10 conditional
SUBTTL PAGFRE - Determine if a given page is free or not
;CALL S1/PAGE NUMBER OF PAGE IN QUESTION
;
;TRUE RETURN: S2/0 ;IF PAGE IS FREE
; OR
; S2/1 ;IF PAGE IS IN USE
TOPS10 <
PAGFRE: MOVE S2,S1 ;GET ARGUMENT (PAGE NR.)
HRLI S2,.PAGCA ;GET PAGE ACCESS
PAGE. S2, ;LOOK UP PAGE ACESS CODE
$STOP(PEF,Page existence check failed)
TXNE S2,PA.GNE ;DOES PAGE EXIST?
TDZA S2,S2 ;NO, RETURN 0, I.E. PAGE IS FREE
MOVX S2,1 ;YES, MARK IT AS IN USE
$RETT ;IN EITHER CASE, RETURN
> ;END TOPS10 CONDITIONAL
TOPS20 <
PAGFRE: HRLI S1,.FHSLF ;CHECK FOR THIS PROCESS
RPACS ;THE PAGE ACCESSABLITY
ERCAL [$STOP(PEF,Page existence check failed)]
TXNN S2,PA%PEX ;DOES PAGE EXIST?
TDZA S2,S2 ;NO, RETURN THAT PAGE IS FREE
MOVX S2,1 ;OTHERWISE MARK ITS USE
ANDI S1,-1 ;PUT JUST PAGE NUMBER BACK INTO S1
$RETT ;AND RETURN
> ;END TOPS20 CONDITIONAL
SUBTTL M%GPAG - Acquire one free page full of zeroes (address)
;This routine is called to acquire one free page (zeroed).
;
;Call: no arguments
;
;T Ret: S1/ address of first word of page acquired
M%GPAG: PUSHJ P,M%ACQP ;GET A PAGE
PG2ADR S1 ;CONVERT PAGE NUMBER TO ADDRESS
$RETT ;AND RETURN
SUBTTL M%ACQP - Acquire one free page full of zeroes (page number)
;THIS ROUTINE IS CALLED TO ACQUIRE A SINGLE FREE PAGE
;
;TRUE RETURN: S1/PAGE NUMBER OF ACQUIRED PAGE
;
;FALSE RETURN: NEVER, STOP CODE "ASE" INSTEAD
;
M%ACQP: MOVEI S1,1 ;WILL ASK FOR 1 PAGE
SKIPG AVBPGS ;ANY "GOOD" PAGES AVAILABLE?
JRST M%AQNP ;NO, TAKE ANY AVAILABLE PAGE
MOVE S1,PAGSTA ;GET STARTING POINT FOR SEARCH
ACQP.1: CAIL S1,MEMSIZ ;OFF THE TOP OF MEMORY
$STOP(CAC,Count of Available Pages Confused)
MOVE S2,PAGTBL(S1) ;GET PAGE FLAGS
TXC S2,PT.ADR ;WANT TO TEST FOR ON
TXNE S2,PT.USE!PT.ADR ;IS IT FREE AND IN-CORE NOW
AOJA S1,ACQP.1 ;NOT THE BEST, TRY THE NEXT
PJRST CREPAG ;EXIT, CREATING AND ZEROING PAGE "S1"
SUBTTL M%AQNP - Acquire several free pages full of zeroes
;CALL IS: S1/NUMBER OF PAGES DESIRED (MAYBE 1 TO MEMSIZ, BUT NOT 0)
;
;TRUE RETURN: S1/PAGE NUMBER OF FIRST PAGE ACQUIRED
;
;FALSE RETURN: NEVER, STOP CODE "ASE" INSTEAD
M%AQNP: SKIPG S1 ;WANTS 1 OR MORE PAGES, RIGHT?
$STOP(RZP,Request for zero pages) ; NO, SO STOP NOW
PUSHJ P,.SAVE3 ;SAVE A COUPLE FIRST
MOVE P1,S1 ;GET THE NUMBER REQUESTED
AQNP.0: MOVE S1,PAGSTA ;FIRST PAGE TO TRY FOR
MOVEI P2,-1(P1) ;COPY THE COUNT FOR THE LOOP BELOW
PUSHJ P,FNDPAG ;GET A PAGE
JUMPF AQNP.3 ;IF NO PAGES, TRY TO ROB CHUNK POOL
JUMPE P2,AQNP.2 ;DONE IF ONLY WANTS ONE
AQNP.1: MOVE P3,S1 ;SAVE THAT NUMBER
PUSHJ P,[ AOJA S1,FNDPAG] ;TRY NEXT PAGE NOW
JUMPF AQNP.3 ;IF FAILS, TRY COLLECTING
CAIE S1,1(P3) ;ARE THEY CONTIGUOUS?
MOVEI P2,(P1) ;NO, RESET LOOP COUNT
SOJG P2,AQNP.1 ;GET MORE IF REQUIRED
AQNP.2: PUSHJ P,CREPAG ;CREATE PAGE "S1"
SOJLE P1,.RETT ;RETURN IF ALL DONE
SOJA S1,AQNP.2 ;ELSE BACK DOWN TO THE NEXT ONE
AQNP.3: SKIPE PANFLG ;CALL FROM M%GMEM?
JRST S..ASE ;YES, ITS ALL OVER
PUSHJ P,PGCOLL ;COLLECT PAGES FROM CHUNK ODD SIZE POOL
JUMPT AQNP.0 ;IF WE GOT A PAGE, TRY ALL OVER
$STOP(ASE,Addressing space exhausted) ;ELSE, REALLY NO CORE LEFT
SUBTTL FNDPAG - Find first free page
;CALL IS: S1/ STARTING POINT FOR THE SEARCH
;TRUE RETURN: S1/ FIRST FREE PAGE
;FALSE RETURN: COULD NOT FIND A FREE PAGE
FNDPAG: CAIL S1,MEMSIZ ;ONLY WANT PAGES THAT ARE UNUSED
$RETF ;IF CAN'T FIND ONE, FAIL RETURN
LOAD S2,PAGTBL(S1),PT.USE ;THIS ONE USED
JUMPE S2,.RETT ;NO, TAKE THIS ONE
AOJA S1,FNDPAG ;TRY ANOTHER
SUBTTL CREPAG - Routine to create a page
TOPS20 <
CREPAG: MOVE S2,PAGTBL(S1) ;GET OLD SETTINGS
TXNE S2,PT.ADR ;ADDRESSABLE
SOS AVBPGS ;DECREMENT COUNT OF "GOOD" PAGES
MOVX S2,PT.USE!PT.ADR ;GET ALL THE BITS
IORM S2,PAGTBL(S1) ;INCLUDE THEM
PUSHJ P,REDUCE ;REDUCE COUNT OF FREE CORE
PJRST .ZPAGN ;RETURN, ZEROING THE PAGE
> ;END TOPS20 CONDITIONAL
TOPS10 <
CREPAG: PUSHJ P,REDUCE ;REDUCE COUNT OF FREE PAGES
MOVX S2,PT.USE ;GET THE INUSE BIT
IORB S2,PAGTBL(S1) ;SET IN USE, GET THE OTHERS
TXNE S2,PT.ADR ;IS IT ADDRESSABLE
JRST [SOS AVBPGS ;YES--DECREMENT "GOOD" PAGES
PJRST .ZPAGN] ;AND RETURN ZEROING PAGE
PUSHJ P,.SAVE4 ;SAVE P1-P4
CREP.1: MOVE P3,S1 ;ARGUMENT FOR CREATE A PAGE
MOVEI P2,1 ;ONLY 1 ARGUMENT
MOVE P1,[.PAGCD,,P2] ;FUNCTION CREATE/DESTROY,,ARGUMENTS
PAGE. P1, ;TRY THE CREATE
JRST CREP.3 ;ANALYZE THE ERROR
CREP.2: MOVX S2,PT.ADR ;ADDRESSABLE
IORM S2,PAGTBL(S1) ;INCLUDE THE FLAG
PJRST .ZPAGN ;RETURN, ZEROING THE PAGE
CREP.3: PUSH P,S1 ;SAVE THE PAGE WE'RE TRYING TO CREATE
CAIE P1,PAGNS% ;OUT OF SWAPPING SPACE
JRST CREP.5 ;NO, LOOK AGAIN
CREP.4: MOVEI S1,5 ;TAKE A QUICK NAP FIRST
SLEEP S1, ;IN CASE SOME FREES UP
PUSHJ P,M%CLNC ;FREE SOME SWAPPING SPACE
POP P,S1 ;RESTORE PAGE NUMBER
JRST CREP.1 ;AND RETRY THE CREATE
CREP.5: CAIE P1,PAGLE% ;MY LIMIT EXCEEDED
$STOP(CCP,Cannot create page) ;
MOVE P1,[.PAGCD,,P2] ;GET UUO POINTER AGAIN
TXO P3,PA.GCD ;CREATE ON DISK FLAG
PAGE. P1, ;TRY IT VIRTUALLY
JRST CREP.6 ;LOOK AT ERROR
POP P,S1 ;RESTORE PAGE NUMBER
JRST CREP.2 ;SUCCEED
CREP.6: CAIE P1,PAGNS% ;NO MORE SWAP SPACE?
$STOP (NFP,<No free pages>) ;NO
TXZ P3,PA.GCD ;FIX CREATE-ON-DISK FLAG
JRST CREP.4 ;WAIT FOR SPACE TO FREE UP
> ;END TOPS10 CONDITIONAL
SUBTTL M%NXPG - Acquire the number of a free page for IPCF reception
;CALL NO ARGUMENTS
;
;TRUE RETURN: S1/THE PAGE NUMBER AVAILABLE FOR IPCF RECEIVE
;FALSE RETURN: S1/?, NO PAGES AVAILABLE AT THIS TIME, TRY LATER
;
; AFTER THE RECEIVE, A CALL TO M%IPRC IS REQUIRED.
M%NXPG:
NXPG.0: MOVE S1,FREPGS ;GET COUNT OF FREE PAGES
CAILE S1,IPCPAD ;ENOUGH TO HANDLE AN INCOMING MESSAGE
JRST NXPG.1 ;YES, GO TAKE ONE
PUSHJ P,PGCOLL ;NO, TAKE ONE FROM THE FREE SPACE
JUMPF .RETF ;CAN'T GET ONE, RETURN FALSE
JRST NXPG.0 ;TRY UNTIL ENOUGH FREE
TOPS20 < ;TOPS20 WILL REPLACE ANY EXISTING PAGE WITH THE MESSAGE
NXPG.1: MOVE S1,PAGSTA ;WHERE TO START LOOKING
PUSHJ P,FNDPAG ;GRAB AN AVAILABLE PAGE
SKIPT ;GREAT IF WE GOT ONE
$STOP(CFC,Count of Free Pages Confused)
MOVX S2,PT.USE ;SET THE TEMP STATE
IORB S2,PAGTBL(S1) ;OF INUSE BUT NOT ADDRESSABLE
TXNE S2,PT.ADR ;TAKE ONE OF THE "NICE" PAGES?
SOS AVBPGS ;YES, REDUCE COUNT OF THEM NOW
MOVX S2,PT.ADR ;GET THESE FLAGS
ANDCAM S2,PAGTBL(S1) ;CLEAR THE FLAGS TO BE SAFE
$RETT ;AND TAKE A GOOD RETURN
> ;END TOPS20 CONDITIONAL
TOPS10 < ;TOPS10 REQUIRES A NON-EXISTANT PAGE
NXPG.1: PUSHJ P,NXPG.3 ;FIND A COMPLETELY MISSING PAGE
JUMPT NXPG.2 ;TAKE THIS ONE IF WE CAN
PUSHJ P,M%CLNC ;DESTROY ANY PAGES I CAN
PUSHJ P,NXPG.3 ;NOW TRY TO FIND ONE
SKIPT ;GREAT IF WE GOT ONE
$STOP(CFC,Count of Free Pages Confused)
NXPG.2: MOVX S2,PT.USE ;SET THE TEMP STATE
IORM S2,PAGTBL(S1) ;OF INUSE BUT NOT ADDRESSABLE
$RETT ;RETURN OUR SUCCESS
NXPG.3: MOVE S1,PAGSTA ;START AT THE FIRST AVAILABLE PAGE
NXPG.4: CAIL S1,MEMSIZ ;END OF THE ADDRESSING SPACE
$RETF ;YES, RETURN A FAILURE
MOVE S2,PAGTBL(S1) ;GET THE TABLE ENTRY
TXNN S2,PT.USE!PT.ADR ;IS THIS PAGE THERE
$RETT ;NO BITS MEANS OK TO USE IT
AOJA S1,NXPG.4 ;WELL, TRY THE NEXT
> ;END TOPS10 CONDITIONAL
SUBTTL M%RLNP - Release contiquous free pages
;CALL IS: S1 / NUMBER TO RELEASE
; S2 / THE FIRST PAGE
;
;TRUE RETURN: ALWAYS
M%RLNP: PUSHJ P,.SAVE2 ;SAVE P1 AND P2
DMOVE P1,S1 ;COPY THE ARGS OVER
RLNP.1: SOJL P1,.RETT ;DECR THE COUNT AND RTN ON 0
MOVE S1,P2 ;GET THE PAGE NUMBER
PUSHJ P,M%RELP ;RELEASE IT
AOJA P2,RLNP.1 ;AND LOOP
SUBTTL M%RELP - Release a single page to the free pool (by page number)
SUBTTL M%RPAG - Release a single page to the free pool (by address)
;CALL IS: S1/ PAGE NUMBER TO RELEASE
;
;TRUE RETURN: ALWAYS
M%RPAG: ADR2PG S1 ;CONVERT ADR TO PAGE
; AND FALL INTO M%RELP
M%RELP: PUSHJ P,VALPAG ;CONSISTENCY CHECK PAGE NUMBER
MOVE S2,PAGTBL(S1) ;GET THE FLAGS
TXNE S2,PT.ADR ;IS THIS THE ONE IPCF'ED AWAY
JRST RELP.1 ;NO, GO FIX THE COUNTS
ZERO PAGTBL(S1) ;CLEAR THE ENTRY
$RETT ;AND RETURN
RELP.1: PUSHJ P,.SAVE1 ;SAVE AN AC
MOVEI P1,PAGTBL(S1) ;SAVE ADDRESS OF PAGTBL ENTRY
PUSHJ P,INCLUD ;BUMP FREE PAGE COUNT
AOS S1,AVBPGS ;BUMP COUNT OF AVAILABLE PAGES
CAILE S1,PAGAVL ;EXCEED WORKING SET SIZE
PUSHJ P,M%CLNC ;YES..CLEANUP MEMORY
RELP.2: TXZ S2,PT.USE ;CLEAR IN USE
MOVEM S2,(P1) ;SAVE THE ENTRY IN PAGE TABLE
$RETT ;NOW RETURN..
;THIS WILL ALWAYS LEAVE ONE PAGE
;FOR AVBPGS
SUBTTL M%FPGS - Return number of free pages
;CALL NO ARGUMENTS
;
;TRUE RETURN: ALWAYS, S1/THE NUMBER OF PAGES FREE
M%FPGS: MOVE S1,FREPGS ;PICK UP THE NUMBER
$RETT ;AND RETURN
SUBTTL M%IPSN - Inform that page is about to be sent via IPCF
; CALL IS: S1/ PAGE NUMBER OF IPCF'ED PAGE
;
;TRUE RETURN: ALWAYS
M%IPSN: PUSHJ P,VALPAG ;CONSISTENCY CHECK PAGE NUMBER
MOVX S2,PT.ADR ;CLEAR ADDRESSABLE
ANDCAM S2,PAGTBL(S1) ;SO THAT WE DON'T GET CONFUSED
PJRST INCLUD ;BUMP FREE PAGE COUNT AND RETURN
SUBTTL M%IPRC - Inform that page has been created via IPCF
;CALL IS: S1/PAGE NUMBER THAT RECEIVE CREATED
;
;TRUE RETURN: ALWAYS
TOPS10 < ;NOW NEED TO KNOW IF THE PAGE IS IN THE WORKING SET
M%IPRC: PUSHJ P,VALPAG ;CONSISTENCY CHECK PAGE NUMBER
PUSH P,S1 ;SAVE THE PAGE NUMBER
HRLI S1,.PAGCA ;CHECK ITS ACCESS BITS
PAGE. S1, ;SEE IF THE PAGE IS SWAPPED OUT
$STOP(PAF,Page access check failed)
MOVX S2,PT.ADR ;ADDRESSABLE
TXNE S1,PA.GNE ;PAGE DOESN'T EXIST
$STOP(RNF,Received non-existent page)
POP P,S1 ;RESTORE PAGE NUMBER
IORM S2,PAGTBL(S1) ;INCLUDE THE FLAG(S)
PJRST REDUCE ;REDUCE COUNT OF FREE PAGES AND RETURN
> ;END TOPS10 CONDITIONAL
TOPS20 <
M%IPRC: PUSHJ P,VALPAG ;CONSISTENCY CHECK PAGE NUMBER
MOVX S2,PT.ADR ;ADDRESSABLE
IORM S2,PAGTBL(S1) ;INCLUDE THE FLAGS
PJRST REDUCE ;REDUCE COUNT OF FREE PAGES AND RETURN
> ;END TOPS20 CONDITIONAL
SUBTTL M%GMEM - Allocate a chunk of memory
;CALL IS: S1/ NUMBER OF WORDS WANTED
;
;TRUE RETURN: S1/ NUMBER OF WORDS OBTAINED
; S2/ ADDRESS OF FIRST WORD
M%GMEM: PUSHJ P,.SAVE2 ;GET TWO WORK REGISTERS
CAMG S1,FREWDS ;IN RANGE OF AVAILABLE SPACE?
SKIPG S1 ;OR SILLY NUMBER?
$STOP(RNW,Ridiculous number of words requested)
CAIG S1,DCT.MX ;IF REQUIRED SIZE .GT. DICTIONARY
SKIPN S2,DICT(S1) ;OR IF DICTIONARY ENTRY IS 0
JRST GMEM.0 ;GO TRY THE ODD SIZE POOL
MOVE P1,0(S2) ;GET FORWARD LINK OF CHOSEN BLOCK
MOVEM P1,DICT(S1) ;STORE INTO HEAD AS NEXT TO CHOSE
PJRST .ZCHNK ;RETURN ZEROING CHUNK
GMEM.0: MOVE P1,S1 ;SAVE THE REQUIRED BLOCK LENGTH
MOVE S1,CNT.AP ;GET FREE POOL ALLOCATED PAGE COUNT
CAIL S1,CNK.PM ;WITHIN BOUNDS OF PAGES
PUSHJ P,[PUSHJ P,PGCOLL ;NO,,GARBAGE COLLECT
SETZM CNT.AP ;CLEAR ADDED PAGE COUNT
POPJ P, ] ;RETURN
MOVE S1,P1 ;RESTORE REQUIRED BLOCK LENGTH
GMEM.1: MOVEI S2,DICT ;START WITH HEADER OF ODD LIST
GMEM.2: MOVE P1,S2 ;REMEMBER WHO POINTS TO CURRENT
HRRZ S2,0(P1) ;S2 IS NOW CURRENT BLOCK
JUMPE S2,GMEM.4 ;IF 0, WE HAVE REACHED END OF THE ROAD
HLRZ P2,0(S2) ;GET SIZE OF CURRENT BLOCK
CAMGE P2,S1 ;IS IT SUFFICIENT FOR REQUEST?
JRST GMEM.2 ;NO, SO TRY NEXT BLOCK
GMEM.3: HRL S2,0(S2) ;GET LINK OF CURRENT BLOCK
HLRM S2,0(P1) ;MAKE PREV LINK BE WHAT WAS OUR LINK
HRRZS S2 ;ISOLATE CURRENT BLOCKS ADDRESS
CAMN P2,S1 ;IS THIS AN EXACT MATCH ON SIZE?
PJRST .ZCHNK ;YES, RETURN, ZEROING CHUNK
PUSH P,S1 ;SAVE NUMBER OF WORDS
PUSH P,S2 ;SAVE ADDRESS
ADD S2,S1 ;GET FIRST WORD TO RETURN
SUBM P2,S1 ;NUMBER OF WORDS TO RETURN
PUSHJ P,M%RMEM ;RETURN THE EXTRA WORDS
POP P,S2 ;RESTORE ADDRESS OF BLOCK
POP P,S1 ;RESTORE NUMBER OF WORDS
PJRST .ZCHNK ;YES, RETURN, ZEROING CHUNK
GMEM.4: MOVEI P2,1(S1) ;START WITH NEXT DICT SLOT
GMEM.5: CAILE P2,DCT.MX ;IS THIS STILL INSIDE DICTIONARY?
JRST GMEM.6 ;TIME FOR MORE MEMORY
SKIPN S2,DICT(P2) ;ANYTHING IN THIS DICTIONARY SLOT ???
AOJA P2,GMEM.5 ;NO, TRY NEXT LARGEST
MOVEI P1,DICT(P2) ;P1 IS CELL POINTING TO CHOSEN
JRST GMEM.3 ;EXIT RETURNING EXTRA MEMORY
GMEM.6: PUSH P,S1 ;SAVE SIZE WANTED
PUSHJ P,APMEM ;TRY TO FIX UP FREE CHUNK POOL
POP P,S1 ;RESTORE THE SIZE
JRST GMEM.1 ;AND TRY AGAIN
SUBTTL APMEM - Routine to add one page to the chunk pool
;CALL IS: No arguments
;TRUE RETURN: Always
APMEM: PUSHJ P,.SAVE2 ;GET SOME INDICES
SETOM PANFLG ;DON'T WANT ANYTHING TO GO TO DICT
SOSL APCNT ;TIME TO DUMP THE DICTIONARY?
JRST APME.4 ;NO, JUST GET A PAGE
MOVEI P1,DCT.MX ;GET MAXIMUM DICTIONARY ENTRY
APME.1: MOVE P2,DICT(P1) ;GET START OF LINKED LIST FOR SIZE
SETZM DICT(P1) ;CLEAR IT OUT
APME.2: SKIPN S2,P2 ;DO WE HAVE A VALID ADDRESS?
JRST APME.3 ;NO, PROCESS NEXT SIZE
MOVE S1,P1 ;SET SIZE OF CHUNK UP
MOVE P2,0(P2) ;GET LINK TO NEXT BLOCK
PUSHJ P,M%RMEM ;AND RETURN IT
JRST APME.2 ;REPEAT FOR POSSIBLE NEXT BLOCK
APME.3: SOJG P1,APME.1 ;DO FOR ENTIRE DICTIONARY
MOVEI P1,DDCNT ;SET COUNTER AGAIN
MOVEM P1,APCNT ;RESET IT
SETZM PANFLG ;CLEAR PANIC LEVEL FLAG
INCR CNT.DD ;DUMPED DICTIONARY AGAIN
$RETT ;AND RETURN
APME.4: AOS CNT.AP ;BUMP THE ADDED PAGE COUNT
PUSHJ P,M%ACQP ;ACQUIRE A PAGE
SETZM PANFLG ;CLEAR PANIC LEVEL FLAG
MOVE S2,S1 ;GET PAGE NUMBER
PG2ADR S2 ;CONVERT TO AN ADDRESS
MOVEI S1,PAGSIZ ;AND THE SIZE
PJRST M%RMEM ;RETURN, RETURNING TO FREE POOL
SUBTTL PGCOLL - Routine to remove whole pages from chunk free pool
;This routine is called to remove, from the odd-size pool of the chunk
;manager, whole pages so that they are available to routines needing
;whole, page-aligned areas of memory.
;CALL IS: No arguments
;TRUE RETURN: A page has been freed
;FALSE RETURN: No page could be removed
PGCOLL: AOS CNT.CL ;BUMP NUMBER OF TIMES COLLECTED
SETZM APCNT ;FORCE DICTIONARY DUMP
PUSHJ P,APMEM ;TO INSURE FREE POOL IS ALL IN ODD SIZE
PUSHJ P,.SAVE4 ;NEED LOTS OF SCRATCH SPACE
SETZM CNT.PC ;CLEAR COUNT OF PAGES GOTTEN
MOVEI P1,DICT ;SEED HEAD OF LIST AS PREVIOUS
PGCO.1: HRRZ P2,0(P1) ;GET ADDR OF NEXT CHUNK
JUMPE P2,PGCO.2 ;IF 0 LINK, WE ARE AT END
HLRZ P3,0(P2) ;GET LENGTH OF THIS CHUNK
MOVE S1,P2 ;GET ADDRESS OF CHUNK
ADDI S1,PAGSIZ-1 ;AND ROUND UP TO
TRZ S1,PAGSIZ-1 ; PAGE BOUNDARY
MOVE P4,P2 ;COPY ADDRESS OF THIS CHUNK
ADD P4,P3 ;COMPUTE FIRST ADDR NOT IN THIS CHUNK
MOVE S2,S1 ;GET START OF CHUNK
ADDI S2,PAGSIZ ;ADDR OF PAGE STARTING HERE
CAMGE P4,S2 ;IS SIZE OF PAGE WITH BOUNDS OF CHUNK?
JRST [ MOVE P1,P2 ;NO, SO STEP TO NEXT CHUNK
JRST PGCO.1 ] ;AND TRY AGAIN
MOVE P4,S2 ;REMEMBER END ADDRESS OF PAGE SIZE CHUNK
HRRZ S2,0(P2) ;GET ADDR OF NEXT CHUNK IN CHAIN
HRRM S2,0(P1) ;DE-LINK THIS CHUNK
SUB S1,P2 ;COMPUTE LN. OF LEFT HAND OVERFLOW
MOVE S2,P2 ;AND ADDRESS LH OVERFLOW STARTS AT
SUBI P3,PAGSIZ(S1) ;ADJUST COUNT TO REFLECT 1 PAGE+LH
SKIPE S1 ;IF THERE IS ANY LEFT HAND TO RETURN
PUSHJ P,M%RMEM ;DO SO NOW
DMOVE S1,P3 ;GET SIZE, ADDR OF RH OVERFLOW
SKIPE S1 ;IF THERE IS ANY RH OVERFLOW,
PUSHJ P,M%RMEM ;RETURN IT NOW
INCR CNT.PC ;COUNT PAGES COLLECTED IN THIS MANNER
MOVE S1,P4 ;GET END ADDRESS OF PAGE SIZE CHUNK
SUBI S1,PAGSIZ ;IT STARTS HERE
PUSHJ P,M%RPAG ;RETURN THE PAGE
JRST PGCO.1 ;TRY TO GET SOME MORE
PGCO.2: SKIPG CNT.PC ;DID WE GET ANY
$RETF ;NO..RETURN FALSE
$RETT ;YES..RETURN TRUE
SUBTTL M%RMEM - Routine to de-allocate a memory chunk
;CALL IS: S1/ SIZE OF CHUNK BEING RETURNED
; S2/ ADDRESS OF CHUNK BEING RETURNED
;
;TRUE RETURN: ALWAYS
M%RMEM: PUSHJ P,.SAVE2 ;GET SOME WORK SPACE
PUSHJ P,VALADR ;VALIDATE THE ADDRESS
SKIPG S1 ;REASONABLE AMOUNT BEING RETURNED?
$STOP(ZWR,Zero words of memory returned)
SKIPE PANFLG ;ARE WE IN PANIC MODE?
JRST RMEM.1 ;YES, DON'T RETURN TO DICTIONARY
CAIL S1,DCT.MN ;LESS THAN SMALLEST OR
CAILE S1,DCT.MX ;GREATER THAN MAXIMUM IN DICT?
JRST RMEM.1 ;YES, RETURN TO ODD-SIZE POOL
MOVE P1,DICT(S1) ;GET LINK OF HEADER
HRRZM P1,0(S2) ;MAKE IT CURRENT BLOCK'S HEADER
HRRZM S2,DICT(S1) ;AND MAKE HEADER POINT TO CURRENT
$RETT ;RETURN NOW
RMEM.1: MOVEI P1,DICT ;GET PREV SET UP
RMEM.2: HRRZ P2,0(P1) ;GET PREV'S LINK
SKIPE P2 ;IF CURRENT IS 0 OR
CAIL P2,0(S2) ; ITS ADDRESS IS PAST ADDR OF RETURN BLK
JRST RMEM.3 ; THEN RETURN BLOCK HERE
MOVE P1,P2 ;MAKE PREV=CURRENT
JRST RMEM.2 ;CONTINUE
RMEM.3: HLRZ P2,0(P1) ;GET SIZE OF PREVIOUS
ADD P2,P1 ;ADD SIZE PLUS ADDRESS
CAIE P2,0(S2) ;DOES THIS PUT IT AT CURRENT BLOCK?
JRST RMEM.4 ;NO, CANNOT COMBINE
MOVE S2,P1 ;CONCATENATE PREV AND CURRENT
HLRZ P2,0(P1) ;GET SIZE OF PREVIOUS AGAIN
ADD S1,P2 ;MAKE A COMBINED SIZE
RMEM.4: HRLM S1,0(S2) ;STORE SIZE OF CURRENT BLOCK
HRRZ P2,0(P1) ;GET PREV'S FORWARD LINK
HRRM P2,0(S2) ;MAKE IT CURRENT'S FORWARD LINK
CAME S2,P1 ;UNLESS PREV=CURRENT (FROM CONCATENATION)
HRRM S2,0(P1) ;MAKE PREV'S FORWARD LINK POINT TO CURR.
MOVE P1,S2 ;GET ADDRESS OF CURRENT BLOCK
ADD P1,S1 ;ADD SIZE TO THAT
CAIE P1,0(P2) ;DO WE BUTT UP AGAINST NEXT?
$RETT ;NO, CANNOT COMBINE, RETURN NOW
HRLZS S1 ;YES, POSITION SIZE OF CURRENT
ADD S1,0(P2) ;MAKE COMBINED SIZE,,LINK TO NEW NEXT
MOVEM S1,0(S2) ;STORE NEW SIZE AND LINK
$RETT ;RETURN
SUBTTL Consistency checking routines
;"REDUCE" DECREMENTS THE FREE PAGE COUNT , "INCLUD" ADDS A FREE PAGE
;
REDUCE: SOSGE FREPGS ;DECREMENT COUNT OF FREE PAGES
$STOP(FCN,Free count negative)
$RETT ;RETURN IF OK
INCLUD: AOS S1,FREPGS ;ADD A FREE PAGE
CAMLE S1,FREINI ;MORE THAN WE STARTED OUT WITH
$STOP(FCE,Free count exceeds FREINI)
$RETT ;RETURN IF OK
;VALADR VALIDATES THE RANGE OF MEMORY THAT STARTS AT ADDR IN S2
; AND CONTINUES FOR THE NUMBER OF WORDS IN S1
VALADR: PUSH P,S1 ;SAVE INPUT ARGUMENTS
PUSH P,S2 ;FROM M%RMEM
EXCH S1,S2 ;GET ADDRESS IN S1, SIZE IN S2
ADR2PG S1 ;CONVERT TO A PAGE NUMBER
VALA.1: PUSHJ P,VALPAG ;VALIDATE IT
SUBI S2,PAGSIZ ;HAVE ACCOUNTED FOR ONE PAGE
SKIPLE S2 ;DONE ENTIRE CHUNK?
AOJA S1,VALA.1 ;NO, DO THE NEXT PAGE
POP P,S2 ;RESTORE S2 (ADDRESS)
POP P,S1 ;RESTORE S1 (SIZE)
$RETT ;AND RETURN
;VALPAG VALIDATES THE PAGE NUMBER IN AC S1
VALPAG: CAIL S1,MEMSIZ ;RANGE CHECK THE PAGE NUMBER
JRST S..BPN ;OUT OF RANGE OF PAGE TABLE
PUSH P,S2 ;SAVE CALLER'S AC
MOVE S2,PAGTBL(S1) ;GET THE PAGE TABLE ENTRY FOR PAGE
TXNN S2,PT.INI ;PART OF INITIAL CORE IMAGE?
TXNN S2,PT.USE ;OR NOT IN USE?
$STOP(BPN,Bad page number ^O/S1/) ;YES, STOP NOW
POP P,S2 ;RESTORE CALLER'S S2
$RETT ;RETURN IF OK
SUBTTL M%CLNC - Routines for cleaning up core
;CALL IS: NO ARGUMENTS
;
;TRUE RETURN: ALWAYS
M%CLNC:
TOPS10 < ;TOPS-10 ONLY
PUSHJ P,.SAVE4 ;SAVE P1-P4
MOVE P4,PAGSTA ;THE FIRST AVAILABLE PAGE
CLNC.1: CAIL P4,MEMSIZ ;OFF THE END OF THE WORLD
$RETT ;YES, RETURN
MOVE P1,PAGTBL(P4) ;GET THE TABLE ENTRY
TXC P1,PT.ADR ;NEED CHECK FOR BOTH SO FLIP
TXNN P1,PT.USE!PT.ADR ;USED OR NOT ADDRESSABEL
PUSHJ P,KILPAG ;DESTROY THE PAGE (COULD BE PAGED OUT)
AOJA P4,CLNC.1 ;AND CONTINUE LOOPING
KILPAG: MOVEI P3,(P4) ;WANT IT IN P3
TXO P3,1B0 ;SET TO DESTROY
MOVEI P2,1 ;1 ARGUMENT
MOVE P1,[.PAGCD,,P2] ;CREATE/DESTROY,,ARGUMENT
PAGE. P1, ;TRY TO DESTROY IT
$STOP(PKF,Page kill failed)
ZERO P1 ;CLEAR A REG
EXCH P1,PAGTBL(P4) ;CLEAR PAGE TABLE ENTRY, GET OLD FLAGS
SOS AVBPGS ;ONE LESS "GOOD" PAGE
$RETT ;RETURN
> ;END OF TOPS-10 CONDITIONAL
TOPS20 <$RETT> ;TOPS-20 ONLY
SUBTTL M%IPRM - Routine to find a free page for an IPCF receive
; M%IPRM will find a free page for an IPCF receive. To do this
; correctly in all cases, we create a page on disk, fault it into
; core, and destroy it. This leaves us a slot in our working set
; to receive an IPCF packet.
; Call: $CALL M%IPRM
;
; TRUE return: a page free in the working set
; FALSE return: can't find a free page
;
M%IPRM:
TOPS10 < ;TOPS-10 ONLY
PUSHJ P,.SAVE3## ;SAVE SOME ACS
PUSHJ P,M%NXPG ;GET A NON-EXISTANT PAGE NUMBER
JUMPF IPRM.E ;CAN'T
MOVE P1,[.PAGCD,,P2] ;SET UP UUO
MOVEI P2,1 ;ONE WORD ARGUMENT
MOVE P3,S1 ;GET THE PAGE NUMBER
TXO P3,PA.GCD ;CREATE THE PAGE ON DISK
PAGE. P1, ;CREATE THE PAGE
JRST IPRM.E ;CAN'T
MOVE P1,S1 ;GET THE PAGE NUMBER
PG2ADR P1 ;CONVERT TO AN ADDRESS
MOVE S2,(P1) ;PAGE FAULT IT INTO CORE
MOVE P1,[.PAGCD,,P2] ;SET UP UUO
MOVEI P2,1 ;ONE WORD ARGUMENT
MOVE P3,S1 ;GET THE PAGE NUMBER
TXO P3,PA.GAF ;LITE THE DESTROY BIT
PAGE. P1, ;DESTROY THE PAGE
SKIPA ;CAN'T
;**[30] Insert 1 line at M%IPRM+21L. /LWS
SETZM PAGTBL(S1) ;[30] PAGE NO LONGER AROUND
$RETT ;RETURN
IPRM.E: $RETE (NFP) ;?NO FREE PAGES
> ;END OF TOPS-10 CONDITIONAL
TOPS20 <$RETT> ;TOPS-20 ONLY
SUBTTL End
MEM%L:
END