Re: [sv-bc] Type of a concat expression

Hi Gordon,
I have looked at table 11-21. That is all related to bit length
calculation of expression, nothing related to type of expression. And
also sections 11.6 - 11.8 all talk about the evaluation rule of
expression, but not about the type. But if you have an expression inside
a type operator and used in comparison rule with another type operator,
it needs specific rule to check which is missing in LRM I can see. For
e.g. what is a type of a binary operator consisting of two numbers:

initial
    if (type(100 + 2'b11) == type (int)) // Will it match or not?
       x = 1;
    else
       x = 2;

Regarding 2-state/4-state, a logic can contain both 2-state and 4-state
values. So it is not clear whether following comparison will match or not:

typedef logic[1:0] mylogic;
type (type({1'b1, 1'b0}) == type (mylogic))

I think LRM should have some guidelines to clarify all.

Regards
Surya

-------- Original Message --------
Subject: Re:[sv-bc] Type of a concat expression
From: Gordon Vreugdenhil <gordonv@model.com>
To: Surya Pratik Saha <spsaha@cal.interrasystems.com>
Cc: "sv-bc@eda.org" <sv-bc@eda.org>, "'Pradip Mukhopadhyay'"
<pradip@cal.interrasystems.com>, Subhankar Ghosh
<sghosh@cal.interrasystems.com>
Date: Monday, June 14, 2010 10:09:44 PM
> Have you looked at Table 11-21? And generally Section 11.6 - 11.8 in
> 1800-2009?
>
> If you have a specific question about a specific rule application, please
> do ask. But first, carefully work through Clause 11; there are many
> rules
> covering self-determined result types for expressions.
>
> The rules in SV are not trivial, but they are in the LRM.
>
> Gord.
>
>
> Surya Pratik Saha wrote:
>> Hi Shalom,
>> Thanks for your response. But I think we should have a list of all
>> self determined result type of an expression. For e.g. what is the
>> type of a binary expression?
>>
>> Regards
>> Surya
>>
>>
>>
>> -------- Original Message --------
>> Subject: Re:[sv-bc] Type of a concat expression
>> From: Bresticker, Shalom <shalom.bresticker@intel.com>
>> To: Surya Pratik Saha <spsaha@cal.interrasystems.com>, sv-bc@eda.org
>> <sv-bc@eda.org>
>> Cc: "'Pradip Mukhopadhyay'" <pradip@cal.interrasystems.com>,
>> Subhankar Ghosh <sghosh@cal.interrasystems.com>
>> Date: Monday, June 14, 2010 5:44:29 PM
>>> The LRM says (11.4.12)
>>>
>>> "The concatenation is treated as a packed vector of bits...One or
>>> more bits of a concatenation can be selected as if the concatenation
>>> were a packed array with the range [n-1:0]."
>>>
>>> and (11.8.1)
>>>
>>> "— Concatenate results are unsigned, regardless of the operands."
>>>
>>> Note that 'byte' is signed.
>>>
>>> Shalom
>>>
>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>> *From:* owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] *On
>>> Behalf Of *Surya Pratik Saha
>>> *Sent:* Monday, June 14, 2010 3:04 PM
>>> *To:* sv-bc@eda.org
>>> *Cc:* 'Pradip Mukhopadhyay'; Subhankar Ghosh
>>> *Subject:* [sv-bc] Type of a concat expression
>>>
>>> Hi,
>>> What should be the return value of a "type ({b1, b2})"? LRM
>>> section 6.23 (Type operator) mentions following text:
>>> *The type operator applied to an expression shall represent the
>>> self-determined result type of that expression.
>>>
>>> *But I could not find anywhere self-determined result type defined
>>> of an expression.
>>> One of the standard simulators which supports type operator works
>>> in its own way.
>>>
>>> Here is a sample example:
>>> module top(input bit in1, input bit[31:0] in2, output
>>> bit [7:0] out1);
>>> bit [3:0] f0, f1; bit [3:0] l1;
>>> initial
>>> begin : blk
>>> if(type ({f0, f1}) == type (byte))
>>> out1 = 1;
>>> else out1 = 3;
>>> end
>>> endmodule
>>>
>>> -- Regards
>>> Surya
>>>
>>>
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>>
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