[sv-bc] Proposed BNF replacement for A.2.9 (modports)

Subject: [sv-bc] Proposed BNF replacement for A.2.9 (modports)
From: Brad Pierce (Brad.Pierce@synopsys.com)
Date: Mon Jan 20 2003 - 09:07:17 PST

• Next message: Karen Pieper: "[sv-bc] Fwd: FW: Inconsistent use of error/warnings on priority/unique keyword s"
• Previous message: Brad Pierce: "Re: [sv-bc] Brad Pierce's AR from 15/01/03"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

------------------ Proposal ----------------------------------------

Replace A.2.9 with --

  modport_declaration
           ::=
               'modport' modport_item { ',' modport_item } ';'

  modport_item
           ::=
               modport_identifier '(' modport_ports_declaration
                           { ',' modport_ports_declaration } ')'

  modport_ports_declaration
           ::=
               modport_simple_ports_declaration
             | modport_hierarchical_ports_declaration
             | modport_tf_ports_declaration

  modport_simple_ports_declaration
           ::=
               'input' list_of_modport_port_identifiers
             | 'output' list_of_modport_port_identifiers
             | 'inout' list_of_modport_port_identifiers

  modport_hierarchical_ports_declaration
           ::=
               interface_instance_identifier
                              { '[' constant_expression ']' }
                      . modport_identifier

  modport_tf_ports_declaration
           ::=
               import_export modport_tf_port
                              { ',' modport_tf_port }

  modport_tf_port
           ::=
               'task' named_task_proto
             | 'function' named_function_proto
             | task_or_function_identifier

  import_export
           ::=
               'import'
             | 'export'

-------

Add to A.9.3 --

  interface_instance_identifier
           ::=
               identifier
-------

Add to A.2.3 --

  list_of_modport_port_identifiers
           ::=
               port_identifier { ',' port_identifier }

-------------- Motivations ----------------------------------

   1) In an hierarchical interface, modport ports can
       themselves be from modports of interface instances.
       And those instances can be arrayed or generated,
       just like module instances. So rather than

              interface_identifier . port_identifer

       we need

              interface_instance_identifier {[...]}
                         . modport_identifier

   2) The current BNF uses an ANSI-C style in modports that
       would require repetitive declarations of direction and
       import/export, such as,

           modport master ( input a,
                            input b,
                            output c,
                            output d,
                            import task masterRead(),
                            import task masterWrite() ) ;

       but the SystemVerilog language uses a style consistent
       with Verilog 2001, extending the ANSI-C style to
       something like --

           modport master ( input a, b,
                            output c, d,
                            import task masterRead(),
                                   task masterWrite() ) ;

   3) As noted in http://www.eda.org/sv-bc/hm/0221.html
       the [port_type] should not have been in modport_port
       in the existing BNF.

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

• Next message: Karen Pieper: "[sv-bc] Fwd: FW: Inconsistent use of error/warnings on priority/unique keyword s"
• Previous message: Brad Pierce: "Re: [sv-bc] Brad Pierce's AR from 15/01/03"
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

This archive was generated by hypermail 2b28 : Mon Jan 20 2003 - 09:08:28 PST