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Trailing-Edge - PDP-10 Archives - BB-H138F-BM_1988 - 7-sources/mxnpag.b36
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! UPD ID= 196, SNARK:<6.1.NML>NMUPAG.B36.3,  10-Dec-84 14:59:03 by HALPIN
! Get MONSYM Library file out of default directory, not BLI:
!
! UPD ID= 101, SLICE:<6.1.NML>NMUPAG.B36.2,  18-Sep-84 15:28:54 by GUNN
! WORK:<GUNN.NML>NMUPAG.B36.2 21-Aug-84 11:55:04, Edit by GUNN
!
! Change to accomodate new LIBRARY conventions. MONSYM.L36 and JLNKG.L36
! are now explicity declared here rather than in NMULIB.
!
! NET:<GROSSMAN.NML-SOURCES>NMUPAG.B36.2  8-Mar-82 16:35:54, Edit by GROSSMAN
!
! Rewrite NMU$PAGE_GET so that the Tops-10 stuff is ALL under one conditional.
! This will reduce confusion due to feature tests.
!
! 1-Dec-81 15:31:41, Edit by GROSSMAN, Ident = X00.03
!
! Change a conditional so that WRITE_PROTECT is not used under Tops-10
!
! 14-Nov-81 23:33:33, Edit by GROSSMAN
!
! Fix previous edit so that it can work under Tops-10.
!
! NET:<DECNET20-V3P1.BASELEVEL-2.SOURCES>NMUPAG.B36.7  6-Aug-81 08:55:28, Edit by JENNESS
!
!    Ident 03.
!    Add page write access protection when a page is in the free queue.
!
! NET:<DECNET20-V3P1.BASELEVEL-2.SOURCES>NMUPAG.B36.4  5-Aug-81 13:20:02, Edit by JENNESS
!
!    Ident 02.
!    Add tracing code to aid in debugging.
!    Update copyright notice.
!
module NMUPAG (				! TOPS (36 bit) page memory allocator
		ident = 'X00.03',
		language (bliss36)
		) =
begin
!
!                         COPYRIGHT (C) 1981
!    DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASSACHUSETTS  01754
!
! THIS SOFTWARE IS FURNISHED  UNDER A LICENSE FOR USE ONLY ON A SINGLE
! COMPUTER  SYSTEM AND  MAY BE  COPIED ONLY 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
! EXCEPT FOR USE ON SUCH SYSTEM AND TO ONE WHO AGREES TO THESE LICENSE
! TERMS.  TITLE TO AND  OWNERSHIP OF THE  SOFTWARE  SHALL AT ALL TIMES
! REMAIN IN DEC.
!
! THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE
! AND SHOULD  NOT BE CONSTRUED  AS A COMMITMENT  BY DIGITAL  EQUIPMENT
! CORPORATION.
!
! DEC ASSUMES  NO  RESPONSIBILITY  FOR  THE USE OR  RELIABILITY OF ITS
! SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DEC.
!

!++
! Facility: LSG DECnet Network Management
!
! Abstract: This module contains the routines needed to handle
!           "page" (512 36 bit word) allocations.
!
! Environment: TOPS10/TOPS20 user mode, MCB RSX user task
!
! Author: Steven M. Jenness, Creation date: 16-Sep-80
!
!--
!
! Include files
!

library 'MXNLIB';			! All required definitions

%if $TOPS20
    %then
	library 'MONSYM';			! Monitor symbols

	library 'MXJLNK';			! JSYS linkage definitions
    %fi

!
! Global routines
!

forward routine
    NMU$PAGE_ALLOCATOR;				! Define global entry points

!
! Data base for page allocator
!

literal
    LOW_PAGE = %O'610000',			! Lowest page number to allocate
    HIGH_PAGE = %O'677000',			! Highest page number to allocate
    PAGE_LENGTH = %O'1000';			! Number of words in a page

own
    NEXT_PAGE : INITIAL (LOW_PAGE),		! Next page to be allocated
    PAGE_QUEUE : Q_HEADER;			! Queue of available pages

!
! Macros
!

%if $TOPS20 %then
macro
     WRITE_ENABLE (ADDR) =
           begin
           DECLARE_JSYS (SPACS);
           if not $$SPACS ((($FHSLF ^ 18) or (ADDR ^ -9)), (PA_WR or PA_RD))
           then TASK_ERROR ('Failed to write enable a page');
           end %,

     WRITE_PROTECT (ADDR) =
           begin
           DECLARE_JSYS (SPACS);
           if not $$SPACS ((($FHSLF ^ 18) or (ADDR ^ -9)), (PA_RD))
           then TASK_ERROR ('Failed to write protect a page');
           end %;
%fi

!
! External references
!

external routine
    NMU$QUEUE_MANAGER;			! Queue management routines

external
    %debug_data_base;
%global_routine ('NMU$PAGE_INITIALIZE') : novalue =

!++
! Functional description:
!
!       This routine initializes the page allocation data
!       base.
!
! Formal parameters: none
!
! Routine value: none
! Side effects:
!
!       NEXT_PAGE is set to LOW_PAGE
!       PAGE_QUEUE is cleared
!
!--

    begin
    NEXT_PAGE = LOW_PAGE;
    NMU$QUEUE_RESET (PAGE_QUEUE);

    %debug (PAGE_TRACE,
            (TRACE_INFO ('Page allocator initialized')));

    end;					! End of NMU$PAGE_INITIALIZE
%global_routine ('NMU$PAGE_GET') =

!++
! Functional description:
!
!       This routine allocates a page (512 words) on TOPS10 and
!       TOPS20 systems.  This is useful for IPCF transactions.
!
! Formal parameters: none
!
! Routine value:
!
!       Page number allocated.
!
! Side effects: none
!
!--

    begin

    local
	PAGE_ADDRESS;

    builtin
	LSH;

    %if $TOPS20 %then
    %debug (always,
            (begin

             if (PAGE_ADDRESS = .PAGE_QUEUE <0,18,0>) neq PAGE_QUEUE
             then WRITE_ENABLE (.PAGE_ADDRESS);

             if (PAGE_ADDRESS = .(.PAGE_ADDRESS) <0,18,0>) neq PAGE_QUEUE
             then WRITE_ENABLE (.PAGE_ADDRESS);
             
             end));

    PAGE_ADDRESS = NMU$QUEUE_REMOVE (PAGE_QUEUE);

    if .PAGE_ADDRESS eql 0 then NEXT_PAGE = (PAGE_ADDRESS = .NEXT_PAGE) + PAGE_LENGTH;

    if (.PAGE_ADDRESS lss LOW_PAGE) or (.PAGE_ADDRESS gtr HIGH_PAGE)
    then TASK_ERROR ('No pages available to be allocated');

    begin
	register T1, T2;
	builtin MACHOP;
	MACHOP (HRLI, T1, .PAGE_ADDRESS);
	MACHOP (HRRI, T1, .PAGE_ADDRESS + 1);
	MACHOP (MOVEI, T2, .PAGE_ADDRESS + PAGE_LENGTH - 1);
	MACHOP (SETZM, 0, .PAGE_ADDRESS);
	MACHOP (BLT, T1, 0, T2);
    end;

    %debug (PAGE_TRACE,
            (TRACE_INFO ('Page %O allocated', LSH (.PAGE_ADDRESS, -9))));

    %debug (always,
            (begin
             local
                  FIRST_PAGE;

             if (FIRST_PAGE = .PAGE_QUEUE <0,18,0>) neq PAGE_QUEUE
             then WRITE_PROTECT (.FIRST_PAGE);

             end));
    %fi ! End of %if $TOPS20
    %if $TOPS10 %then

    if (PAGE_ADDRESS = NMU$QUEUE_REMOVE (PAGE_QUEUE)) eql 0 then
    begin
	builtin UUO;
	register T1;
	local ARGLST : vector [2];

	PAGE_ADDRESS = .NEXT_PAGE;
	NEXT_PAGE = .NEXT_PAGE + PAGE_LENGTH;

	if .PAGE_ADDRESS lss LOW_PAGE or .PAGE_ADDRESS gtr HIGH_PAGE
	then TASK_ERROR ('No pages available to be allocated');

	T1 = $PAGCD ^ 18 + ARGLST;
	ARGLST [0] = 1;
	ARGLST [1] = LSH (.PAGE_ADDRESS, -9) ;
	UUO (1, PAGE$(T1));
    end
    else
    begin
	register T1;
	builtin MACHOP;
	literal HRLZ = %o '514';

	MACHOP	(SETZM, 0, .PAGE_ADDRESS);
	MACHOP	(HRLZ, T1, PAGE_ADDRESS);
	MACHOP	(HRRI, T1, .PAGE_ADDRESS + 1);
	MACHOP	(BLT, T1, .PAGE_ADDRESS + PAGE_LENGTH - 1);
    end;
    %fi

    LSH (.PAGE_ADDRESS, -9)
    end;					! End of NMU$PAGE_GET
%global_routine ('NMU$PAGE_RELEASE', PAGE) : novalue =

!++
! Functional description:
!
!       This routine releases a page that has been allocated
!       using either the NMU$PAGE_GET calls.
!
! Formal parameters:
!
!       PAGE   Page number
!
! Routine value: none
! Side effects: none
!
!--

    begin

    local
         PAGE_ADDRESS;

    builtin
	LSH;

    PAGE_ADDRESS = LSH (.PAGE, 9);

    %if $TOPS20 %then
    %debug (always,
            (begin
             local
                  LAST_PAGE;

             if (LAST_PAGE = .PAGE_QUEUE <18,18,0>) neq PAGE_QUEUE
             then WRITE_ENABLE (.LAST_PAGE);
             end));
    %fi

    %debug (PAGE_TRACE,
            (TRACE_INFO ('Page %O released', .PAGE)));


    if (.PAGE_ADDRESS lss LOW_PAGE) or (.PAGE_ADDRESS gtr HIGH_PAGE)
    then TASK_ERROR ('Attempt to release invalid page');

    NMU$QUEUE_INSERT (PAGE_QUEUE, .PAGE_ADDRESS);

    %if $TOPS20 %then
    %debug (always,
            (begin

             WRITE_PROTECT (.PAGE_ADDRESS);

             if (PAGE_ADDRESS = .(.PAGE_ADDRESS) <18,18,0>) neq PAGE_QUEUE
             then WRITE_PROTECT (.PAGE_ADDRESS);
             
             end));
    %fi

    end;					! End of NMU$PAGE_RELEASE

end						! End of module NMUPAG

eludom
! Local Modes:
! Mode:BLISS
! Auto Save Mode:0
! Comment Column:40
! Comment Rounding:+1
! End: