/*

	The procedure cobol_open_gen.pl1 generates the code which realizes
the COBOL open statement. Two important indicators are involved, cobol_mode
and multics_mode.

	OPEN fn eos

		(repeated if necessary)

		eos	d=00	input
			  01	output
			  10	i-o
			  11	extend

			f=00	rewind
			  01	no-rewind
			  10	reversed

		verb=19

cobol_mode

	1	e, str
	5	e, seq
	17	i, str
	21	i, seq

	25,26,27	i,rel(seq, ran, dyn)
	29,30,31	i,ind(seq, ran, dyn)
	37	i-o, seq

	41,42,43	i-o,rel(seq, ran, dyn)
	45,46,47	i-o, ind(seq, ran, dyn)
	49	o, str

	53	o, seq
	57,58,59	o, rel(seq, ran, dyn)
	61,62,63	o, ind(seq, ran, dyn)



			cobol_mode(multics_mode)		COBOL verbs

	org=seq	i	21(4)	fr	first record	read
		o	53(5)	eof			write
		i-o	37(5,7)	fr			read	rewrite
		e	5(6)	eof(append bit = "1"b)	write

	org=rel

	 acc=seq	i	25(8)	fr			read,start
		o	57(9)	eof.			write
		i-o	41(9,10)	fr			i-verbs	modify

	 acc=ran	i	26(11)	fr			read
		o	58(12)	eof			write
		i-o	42(12,13)	fr			i,o-verbs	modify

	 acc=dyn	i	27(8)	fr			read,start
		o	59(9,10)	fr			write
		i-o	43(9,10)	fr			i,o-verbs	modify

	org=ind

	 acc=seq	i	29(8)	fr			read_next,start
		o	61(9)	eof			write
			61(9,10) if alt keys
		i-o	45(10)	fr			i-verbs	modify

	 acc=ran	i	30(11)	fr			read_key
		o	62(12)	eof			write
		i-o	46(12,13)	fr			i,o-verbs	modify


	 acc=dyn	i	31(8)	fr			read,start
		o	63(9,10)	fr			write
		i-o	47(9,10)	fr			i,o-verbs	modify

	org=str	i	17(1)	fb	first byte
		o	49(2)	eof
		e	1(2)	eof

last_cobol_op

	1 open		5 read_key
	2 close		6 rewrite
	3 start		7 delete
	4 read_next	8 write

multics_mode

	1,2,3		stream_(i o i-o)
	4,5,6,7		seq_(i o i-o u)
	8,9,10		k_s_(i o u)
	11,12,13		d_(i o u)

1 mp based
2  n	fixed bin
2  ptr(1)	ptr	type-1("OPEN")
2  ptr(2)	ptr	type-12(fn)
2  ptr(3) ptr	eos

Flow Chart


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

	alt_output = alt_sw & cobol_mode = 61

TAG(ioerror.retry_tag)

	if	file_table.external
	then	OP30(open_ext_file,good_tag)
	else	OP31(open_int_file,good_tag)

	GEN_IOERROR

TAG(good_tag):

	OP32(find_iocb,iocb_tag)
	GEN_IOERROR

TAG(iocb_tag):

	if file_table.external
	then	OP33(check_attach,attach_tag)

	call ATTACH_OPTIONS_STRING
	OP34(attach_iocb,attach_tag);GEN_IOERROR

TAG(attach_tag):

	OP37(check_file,open_tag1)

	if	alt_output
		|
		cobol_mode = 59	o(rel-dyn)
		|
		cobol_mode = 63	o(ind-dyn)

	then	OP36(open_close_file,open_tag2);GEN_IOERROR

TAG(open_tag2):

	OP35(open_file,open_tag1)

	if	alt_output
		|
		multics_mode = 10		k_s_u
		|
		(	multics_mode = 13	d_u
			&
			cobol_mode < 48	i,o
		)
		|
		multics_mode = 7		seq_u

	then	OP29(close_op_file,open_tag2)

	GEN_IOERROR

TAG(open_tag1):

	if	alt_sw

	then	IO_UTIL$FILE_DESC;OP78(alt_open_file,0);SET_FSBPTR

	if	file_table.linage
	then	OP24(set_line_file_status,0)
	else	OP25(set_file_status,0)

	return;

ATTACH_OPTIONS_STRING:	proc;

	if file_table.device = 7		device is unattached
	then	IOERROR(10)
	else
	if	file_table.eao_len > 0	explicit options
	then	IO_UTIL$MOVE_LIT
	else	do;	if 	file_table.catalogued < 2	no pathname
				&
				file_table.device ^= 5	non-tape

			then	do;
				end;
			else	if file_table.catalogued
				then	do;
					end;
				else	do;
					end;

			if file_table.device = 5	tape
			then	do;
				end;
			else	do;	extend_sw => " -extend"
					file_table.dup__alt => " dup_ok"
				end;

		end;
end;

*/

%include cobol_opr_open;



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


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

*/