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!THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY ONLY BE USED
!  OR COPIED IN ACCORDANCE WITH THE TERMS OF SUCH LICENSE.

!COPYRIGHT (C) DIGITAL EQUIPMENT CORPORATION 1972, 1983
!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 = 7^24 + 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