/*

	The procedure cobol_read_gen.pl1 generates code which realizes the COBOL
read statement .

	READ fn [id] eos

		eos	a=000	neither
			  001	END
			  010	INVALID

			b=0	no INTO
			  1	INTO

			c=0	no KEY
			  1	KEY

			d=00	no NEXT
			  01	NEXT

			e	key number

			f=00	no NOT
			  01	NOT

		verb=21

	mp.n		3-4
	mp.ptr(1)		type-1("READ")
	mp.ptr(2)		type-12(file-name)
	mp.ptr(3)		type-9(INTO id)
	mp.ptr(n)		eos

	org=rel	acc=seq	1: read[next][end]
		acc=ran	1: read[invalid]
		acc=dyn	1: read next[end]
			2: read[invalid]

	org=ind	acc=seq	1: read[next]
		acc=ran	2: read[key][invalid]
		acc=dyn	1: read next[end]
			2: read[key][invalid]

Flow Chart

			read_next_sw =	file_table.access < 2	seq
					|
					end_stmt.d = "01"b		read next

			alt_sw =	file_table.organization = 3	ind
				&
				file_table.alternate_keys ^= 0


TAG(ioerror.retry_error):

	OP63(init_read,ntag)
	GEN_IOERROR

TAG(ntag):

	if file_table.organization = 4	stream
	then	do;	OP64(get_line,ntag);GEN_IOERROR

TAG(ntag):

		end;
	else	do;	if	file_table.access = 3	dyn
				&
				(	file_table.external
					|
					file_table.open_ext
				)

			then	do;	INCR_NTAG
					OP54(delete_error,ntag);GEN_ERROR

TAG(ntag):

				end;

			iosw =	file_table.access < 2	seq
				&
				(	file_table.external
					|
					file_table.delete
					|
					file_table.write
				)

		if	read_next_sw

		then	do;	if	(	file_organization>1	not-seq
						&
						iosw
						&
						file_table.access < 2	seq
					)
					|
					(	file_table.organization = 2	rel
						&
						file_table.relative_key
					)

				then	do;	INCR_NTAG

						OP69(read_key_for_read,ntag);GEN_IOERROR

TAG(ntag):

					end;
				else	do;

			if alt_sw
			then	do;	INCR_NTAG
					IO_UTIL$FILE_DESC
					OP92(alt_find_rec,ntag,skip_read_tag)
TAG(ntag):
					SET_FSBPTR
				end;
					end;

			end
		else	do;	if alt_sw
				then	do;	IO_UTIL$FILE_KEY(0,0)
						IO_UTIL$FILE_DESC
						IO_UTIL$FILE_NUM
						OP84(alt_read_key)
						SET_FSBPTR
					end;

				INCR_NTAG
				OP67(read_seek_key,ntag);GEN_IOERROR


TAG(ntag):

			end;

			INCR_NTAG


			if	read_next_sw

			then	do;	OP65(read_record,ntag)

					if alt_sw then	do;

TAG(skip_read_tag):

							end;
			else	OP66(nonseq_read_tag,ntag)

TAG(ntag):

			if alt_sw
			then	do;	IO_UTIL$FILE_DESC
					SET_FSBPTR

					if read_next_sw
					then	OP80(alt_read_next,0)
					else	OP81(alt_read_key,0)
				end;

		end;

*/

%include cobol_opr_read;



*/
                                          -----------------------------------------------------------


Historical Background

This edition of the Multics software materials and documentation is provided and donated
to Massachusetts Institute of Technology by Group Bull including Bull HN Information Systems Inc. 
as a contribution to computer science knowledge.  
This donation is made also to give evidence of the common contributions of Massachusetts Institute of Technology,
Bell Laboratories, General Electric, Honeywell Information Systems Inc., Honeywell Bull Inc., Groupe Bull
and Bull HN Information Systems Inc. to the development of this operating system. 
Multics development was initiated by Massachusetts Institute of Technology Project MAC (1963-1970),
renamed the MIT Laboratory for Computer Science and Artificial Intelligence in the mid 1970s, under the leadership
of Professor Fernando Jose Corbato. Users consider that Multics provided the best software architecture for 
managing computer hardware properly and for executing programs. Many subsequent operating systems 
incorporated Multics principles.
Multics was distributed in 1975 to 2000 by Group Bull in Europe , and in the U.S. by Bull HN Information Systems Inc., 
as successor in interest by change in name only to Honeywell Bull Inc. and Honeywell Information Systems Inc. .

                                          -----------------------------------------------------------

Permission to use, copy, modify, and distribute these programs and their documentation for any purpose and without
fee is hereby granted,provided that the below copyright notice and historical background appear in all copies
and that both the copyright notice and historical background and this permission notice appear in supporting
documentation, and that the names of MIT, HIS, Bull or Bull HN not be used in advertising or publicity pertaining
to distribution of the programs without specific prior written permission.
    Copyright 1972 by Massachusetts Institute of Technology and Honeywell Information Systems Inc.
    Copyright 2006 by Bull HN Information Systems Inc.
    Copyright 2006 by Bull SAS
    All Rights Reserved

*/