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Trailing-Edge - PDP-10 Archives - BB-JR93L-BB_1990 - 10,7/decmai/mx/mxnpag.b36
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module NMUPAG (				! TOPS (36 bit) page memory allocator
		ident = 'X00.03',
		language (bliss36)
		) =
begin
!	COPYRIGHT (c) DIGITAL EQUIPMENT CORPORATION 1985, 1989.
!	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 THAT IS NOT SUPPLIED BY DIGITAL.
!++
! 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
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