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!COPYRIGHT (C) DIGITAL EQUIPMENT CORPORATION 1972, 1985
!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.

!AUTHOR: S.MURPHY/HPW/TFV

MODULE INPT(RESERVE(0,1,2,3),DREGS=4,SREG=#17,FREG=#16,VREG=#15,GLOROUTINES)=
BEGIN

GLOBAL BIND INPTV = #10^24 + 0^18 + #1530;	! Version Date: 4-May-82

%(

***** Begin Revision History *****

83	-----	-----	INTERFACE TO SKOPTIO

***** Begin Version 7 *****

1530	TFV	4-May-82
	Setup IOLSTATEMENT filed in IOLSCLS nodes.

***** End Revision History *****

)%

SWITCHES NOLIST;
REQUIRE FIRST.BLI;
REQUIRE TABLES.BLI;
SWITCHES LIST;

EXTERNAL
	BASE CSTMNT,
	DOWDP,		! Global used in determining whether a given loop can
			! have its loop index live in a register.
	FOLDIOLST,
	NEGFLG,
	NOTFLG,
	P2SKL1DISP,
	P2SKSTMNT,
%1530%	TOPIO;		! Pointer to the I/O statement above an IOLSCLS node.

GLOBAL ROUTINE SKIOLIST=
BEGIN
	!***************************************************************
	! Perform phase 2 skeleton optimizations on an iolist.  Makes  3
	! passes over the list:
	!
	!	1. Perform  phase  2   skeleton  optimizations  on   the
	!	   expressions under the iolist elements.
	!	2. Detect DO loops  that can be  folded into elists  and
	!	   fold them (not implemented in release 1).
	!	3. Detect groups of DATACALLs and SLISTCALLs that can be
	!	   folded into a single IOLISTCALL and fold them.
	!
	! Called with the global CSTMNT  pointing to a statement with  a
	! potential iolist.
	!***************************************************************

	REGISTER
		PEXPRNODE ARGNODE,
		BASE IOLELEM,
		BASE SAVSTMNT;

	MAP OBJECTCODE DOWDP;

	! Return if this statement has no iolist

	IF .CSTMNT[IOLIST] EQL 0 THEN RETURN;

	! Save pointer to  this statement (will  recurse through  SKSTMN
	! routines if there are any statements on this iolist

	SAVSTMNT = .CSTMNT;

	! Walk down the iolist performing phase 2 skeleton optimizations
	! on each element

	IOLELEM = .CSTMNT[IOLIST];

	UNTIL .IOLELEM EQL 0
	DO
	BEGIN	! Walk down the iolist

		IF .IOLELEM[OPRCLS] EQL STATEMENT
		THEN
		BEGIN
			CSTMNT = .IOLELEM;
			P2SKSTMNT();		! Do skeleton optimizations
		END
		ELSE	IF .IOLELEM[OPRCLS] EQL IOLSCLS
		THEN
		BEGIN
%1530%			! Setup pointer to the I/O statement above the IOLSCLS

%1530%			IOLELEM[IOLSTATEMENT] = .TOPIO;

			! For a DATACALL node, perform phase 2  skeleton
			! optimizations on expressions under this node

			IF .IOLELEM[OPERSP] EQL DATACALL
			THEN
			BEGIN
				NEGFLG = FALSE;
				NOTFLG = FALSE;
				ARGNODE = .IOLELEM[DCALLELEM];
				IOLELEM[DCALLELEM] = (.P2SKL1DISP[.ARGNODE[OPRCLS]])(.ARGNODE);

				! Check whether the argument to FOROTS is  the
				! index of the current DO loop.  If so,  don't
				! make it an AOBJN  loop (problems with  using
				! right-half of register.

				ARGNODE = .IOLELEM[DCALLELEM];

				IF .ARGNODE EQL .DOWDP[DOINDUC]
				THEN DOWDP[DONOAOBJN] = 1;
			END;
		END;

		! Go on to next element

		IOLELEM = .IOLELEM[CLINK];

	END;	! Walk down iolist

	CSTMNT = .SAVSTMNT; 	! Restore CSTMNT

	! Walk down the iolist performing folding  of DO loops into ELISTs  is
	! not implemented in release 1 (Aug 17,1972 - SRM).

	! Walk down the  iolist, folding groups  of elements that  can form  a
	! single IOLISTCALL

	FOLDIOLST();

END;	! of SKIOLIST

END
ELUDOM