RE: [sv-bc] Is member of recursive task/function hierarchically referred?

Hi,

The text you quote is erroneous and was fixed in 1364-2005, which you
should use as reference instead of 1364-2001.

There is no difference in this respect between recursive and
non-recursive automatic functions. 
See http://boyd.com/1364_btf/report/full_pr/325.html.

In your example, the function inc is recursive but not automatic, so it
should be illegal.

Shalom


> -----Original Message-----
> From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On
> Behalf Of Surya Pratik Saha
> Sent: Monday, January 30, 2006 12:44 PM
> To: sv-bc@eda.org
> Subject: [sv-bc] Is member of recursive task/function
> hierarchically referred?
> 
> In 1364-2001 LRM, section 12.4, it is mentioned:
> 
> [...]
> At the top of the name hierarchy are the names of one or more
> root modules of
> which no instances have been
> created.This root or these parallel root modules make up one or
> more hierarchies
> in a design description or
> description .Inside any module,each module instance (including
> an arrayed or
> generated instance),task def-
> inition,function definition,and named begin-end or fork-join
> block shall define
> a new branch of the
> hierarchy.Named blocks within named blocks and within tasks and
> functions shall
> create new branches.
> Only non-recursively referenced automatic tasks and/or
> functions create visible
> branches that can be refer-
> enced.Recursively called tasks and functions,declared using the
> automatic
> keyword and recursively called
> from within the same task or function,do not create visible
> branches that can be
> referenced.See 10.2.1 and
> 10.3.1 for a discussion of automatic tasks and functions.
> [...]
> 
> What I can understand, the member of a directly recursive
> task/function is not
> allowed to be hierarchically referenced. If it is mutually
> recursive, then the
> member can be hierarchically referred unless the task/function
> is automatic.
> 
> It is already mentioned, any member of automatic task/function
> can not be
> hierarchically referred.
> 
> So is the member of a directly recursive task/function allowed
> to be
> hierarchically referred, if the task/function is not automatic.
> If yes, then why
> recursiveness is discussed here.
> 
> For e.g., is the following test case legal?
> module tb;
>    dut dut();
>    initial $dumpvars();
>    endmodule
> 
>    module dut(input clk, input d, output reg [7:0] q);
> 
>       //{remote href,local href, not} X {user dotted, implicit
> dotted}
> 
>       reg [7:0] \t1.local ; // capture?
>       reg [7:0] \literal.local ;
> 
>       function inc (input [7:0] a);
>          reg [7:0] incprev;
>          begin
>             if (a==0)  begin
>               if (d) incprev=0;
>                // else reuse global incprev
>             end
>             else incprev=inc(a-1)+1;
>             inc = incprev;
>          end
>       endfunction
> 
>       task t1 (output [7:0] out, input [7:0] in);
>          reg [7:0] local;
>          begin
>             if (in[0]) local=in>>1;
>             out=local+1;
>          end
>       endtask
> 
>       always @(posedge clk) begin
>          t1(\t1.local , inc(4));
>          q = \t1.local + \literal.local + t1.local +
> inc.incprev;
>       end
> 
>    endmodule
> 
> Regards
> Surya.