Re: Minutes of the Verilog-AMS committee call: 15 May 2008

From: Boris Troyanovsky <boris_at_.....>
Date: Wed May 21 2008 - 11:59:23 PDT
Hi Geoffrey,

I'm not sure when the $mfactor example was added or who the author was.

One thing that I do think should be clarified is whether doing

I(p, n) <+ $mfactor*V(p, n);

is an error or merely a warning. My recollection was that it was intended
to be an error, but the LRM currently mentions both "warning" and "error"
for this situation.

- Boris

> Hi, Boris, et al:
> Anyone know who made up the example with the illegal $mfactor?
> I thought I had let it get into LRM 2.2, but now I see that
> Draft 2 had:
>    NOTE to self: add an example or two to this section
>
> and then Draft3 had that note struck out, but no change-bars
> to indicate that the examples had been added, so maybe that's
> why we hadn't thoroughly reviewed the examples.
>
> I noticed three more glitches:
> 1) module_a in test_module should have .$mfactor(3), else
>     where did the factor of 3 come from?
>
> 2) the line right above Example 2 is a sentence fragment.
>
> 3) In Example 2, module_a is similarly missing .$xposition = 1.1u
>
> -Geoffrey
>
>
>
> Boris Troyanovsky wrote:
>> Hi,
>>
>> I think there may also a pair of issues relating to the $mfactor
>> specification.
>>
>> Issue #1:
>> In section 6.3.6 (p. 123), the LRM states: "The simulator shall issue a
>> warning if it detects a misuse of the $mfactor in a manner that would
>> result in double-scaling." However, just a few lines down, the LRM
>> states:
>> "The simulator will generate an error" for this situation. So I think we
>> should clarify whether this is in fact an error or a warning (my
>> recollection is that the original intent was to make it an error).
>>
>> Issue #2:
>> In Section 9.18 (page 221 / Example 1) the following module has an
>> error:
>>
>> ===========================
>> module module_c(p,n);
>> inout p,n;
>> electrical p,n;
>> parameter r=1.0;
>> analog begin
>> I(p,n) <+ V(p,n)/(r/$mfactor); // the effective resistance = 1/42
>> end
>> endmodule
>> ===========================
>>
>> This usage of $mfactor is prohibited; we can't make explicit
>> contributions
>> that depend on $mfactor. The example should probably be removed or
>> altered.
>>
>> Regards,
>>
>> - Boris
>>
>> --------------------------------------------------------------------------
>>
>>> Hi Sri, Stu,
>>>
>>> I have still a few minor items that I found when scanning again through
>>> the
>>> document:
>>>
>>> p.vii, ToC, item 5.9.3 is in italics while it should be regular
>>> p.14, 2.6.2, 1st line "IEEE STD-754-1985" should use the same notation
>>> as
>>> the references to IEEE 1364 - it should be written as "IEEE std
>>> 754-1985".
>>>
>>> On page 17 in sectins 2.8.3 and 2.8.4 the system tasks and functions
>>> and
>>> the compiler directives are described. However, both these sections
>>> wrongly
>>> say that the Verilog-AMS standard does not introduce new system tasks
>>> or
>>> compiler directives. To remedy that the following changes are needed:
>>>
>>> p.17, 2.8.3, 1st paragraph, 1st line: change "three" into "five".
>>> p.17, 2.8.3, 1st paragraph, two new bullets after the 2nd bullet:
>>> " - Additional $identifier system tasks and functions defined in Clause
>>> 4
>>> and Clause 9 of this standard.", and
>>> " - Additional $identifier system tasks and functions defined using VPI
>>> as
>>> described in Clause 11 and Clause 12 of this standard."
>>> p.17, 2.8.3, 2nd paragraph, remove the last sentence "Additional system
>>> tasks and functions with the $identifier construct are not part of this
>>> standard."
>>> p.17, 2.8.4, 2nd paragraph, 1st line: change "two" to "three".
>>> p.17, 2.8.4, 2nd paragraph, one new bullet after the 1st bullet:
>>> " - Additional `identifier compiler directives defined in Clause 10 of
>>> this
>>> standard."
>>> p.17, 2.8.4, remove last line of the page "Additional compiler
>>> directives
>>> with the `identifier construct are not part of this standard."
>>>
>>> p.209, 9.7.3, the message arguments of the $fatal, $error, $warning,
>>> and
>>> $info system tasks are not described in the text. I propose to add
>>> after
>>> the current last line of the section the following text (taken from
>>> IEEE
>>> 1800-2007, 17.2, p.245, 7th paragraph):
>>>
>>> "Each system task can also include additional user-specified
>>> information
>>> using the same format as the Verilog $display."
>>>
>>> Cheers,
>>> Marq
>>>
>>>
>>> owner-verilog-ams@server.eda.org wrote on 15-05-2008 20:15:57:
>>>
>>>> Stu,
>>>>
>>>> I have minuted the changes discussed in today's meeting. Hopefully i
>>>> have got the points across clearly on the different points (and
>>>> specifically on chapter 9 changes). Please let me know if you need any
>>>> additional clarification on these.
>>>>
>>>> Date: 15 May 2008
>>>>
>>>> Geoffrey Coram, Analog Devices
>>>> Marek Mierzwinski, Tiburon
>>>> Martin O'Leary, Cadence
>>>> Stu Sutherland, Sutherland HDL
>>>> Patrick O'Halloran, Tiburon
>>>> Dave Cronauer, Synospsys
>>>> Ken Bakalar, Mentor Graphics
>>>> Jonathan David, Qualcomm
>>>> Marq Kole, NXP
>>>> Sri Chandra, Freescale
>>>>
>>>> Chapter 1: Verilog-AMS introduction
>>>> * [clause 1.1, pg 15]: remove Verilog-D reference and the text within
>>>> ()
>>>> * [clause 1.1, pg 15]: Add "as described in Annex C" in the Verilog-A
>>>> reference --> ("also referred to as Verilog-A as described in Annex
>>>> C")
>>>>
>>>> Chapter 3: Data types
>>>> * [Syntax 3-2, Pg 41]: In value_range syntax definition, the wrong
>>>> type
>>>> of ` has been used (should not be a back-tick). Same update needs to
>>>> be
>>>> done in Annex A also.
>>>> * [clause 3.4.6, pg 44]: typo on "transistortype"
>>>>
>>>> Chapter 4: Expressions
>>>> * [Table 4-14, pg 71]: Use ">=" for sqrt()
>>>> * [Table 4-15, pg 72]: Use "<=" for acos()
>>>> * [clause 4.5.6, pg 65]: remove ";" in the general form for the ddx()
>>>> expression
>>>> * [clause 4.5.6, pg 65]: move inout declaration before electrical
>>>> declaration in both the diode examples
>>>> * [cluase 4.5.6, pg 65, 66]: font correction (bold) for limexp and vt
>>>> in
>>>> both the diode examples
>>>> * [clause 4.5.11.5, pg 88]: fix font on laplace_zp example for
>>>> "white_noise". Should be bold.
>>>> * [clause 4.6.4, pg 94]: fix the BNF for noise_table (same fix to be
>>>> done in Annex A.8.2)
>>>>    | noise_table (constant_concatenation | string [, string ])
>>>>
>>>> Chapter 6: Hierarchical structures
>>>> * [clause 6.4, pg 140]: The .model card statement should refer to nmos
>>>> instead of nmos3
>>>> * [clause 6.6.2, pg 154]: ";" missing in module pipeline_adc on the
>>>> top
>>>> of the page
>>>>
>>>> Chapter 7: Mixed signal
>>>> * [clause 7.3.2, pg 165]: add "inout anet" to the converter example.
>>>> * [clause 7.3.2, pg 165]: add "output dnet" to the converter example.
>>>> * [clause 7.3.2, pg 165]: The last statement in the analog block
>>>> should
>>>> say V(anet) <+ dnet; instead of V(anet) <+ 1'bz;
>>>>
>>>> Chapter 9: System tasks and functions
>>>> * [syntax 9-8, pg 224]: remove ";"
>>>> * [clause 9.13.1, pg 224]: Remove the first half of the "if" clause in
>>>> the last sentence in paragraph beginning with "The random_seed
>>>> argument
>>>> may take one of several forms"...The last sentence will just read "The
>>>> function returns a new 32-bit random number each time it is called."
>>>> * [clause 9.13.1, pg 224]: In the paragraph starting with "$arandom
>>>> supports the seed argument..."
>>>>    The second sentence should say the following: "The
>>>> analog_random_seed
>>>> argument can also be a parameter or a constant, in which case the
>>>> system
>>>> function does not update the parameter value". (added parameter before
>>>> value to make it more explicit).
>>>> * [clause 9.13.1, pg 224]: Please add the following new sentence after
>>>> the second sentence in the same paragraph:
>>>>    "However an internal seed is created which is assigned the initial
>>>> value of the parameter or constant and the internal seed gets updated
>>>> every time the call to $arandom is made."
>>>> * [clause 9.13.1, pg 224]: Change cross-reference to 6.3 instead of
>>>> 6.4
>>>> * [Syntax 9-9, pg 225]: remove ";" for the distribution functions.
>>>> * [Syntax 9-9, pg 225]: fix font for ")" in rdist_t syntax
>>>> * [clause 9.13.2, pg 225]: In bullet point #3 add the above two fixes
>>>> done for $arandom with parameter seed (adding parameter and inserting
>>>> the new sentence):
>>>>    "... upon successive calls to the system function. If the seed
>>>> argument is parameter or constant, then the system function does not
>>>> update the parameter value. However an internal seed is created which
>>>> is
>>>> assigned the initial value of the parameter or constant and the
>>>> internal
>>>> seed gets updated every time the call to $arandom is made. This makes
>>>> the system function useable for parameter initialization."
>>>>
>>>> Chapter 10: Compiler directives
>>>> * [clause 10.6, pg 254]: ";" missing in "input sin;" in the example at
>>>> the very bottom of the page.
>>>> * [clause 10.6, pg 255]: Add the following note before the example for
>>>> VAMS-2.3
>>>>    Note: The identifier logic is not a keyword in Verilog-AMS v2.3,
>>>> and
>>>> is a keyword in the P1800-2005 System Verilog standard.
>>>> * [clause 10.6, pg 255]: "electrical" and "logic" should not be bold
>>>> in
>>>> the example given to describe VAMS-2.3
>>>>
>>>> Annex A: Formal syntax definition
>>>> * [A.2.5, pg 343]: use correct ` (tick) for the value_range_type.
>>>> * [A.8.2, pg 359]: fix syntax definition for noise_table
>>>>    | noise_table (constant_concatenation | string [, string ])
>>>>
>>>> Annex D: Standard definitions
>>>> * [Annex D.1, pg 372]: domain discrete needs ';'
>>>>
>>>> Annex E: Spice Compatability
>>>> * [Annex E.1.2, pg 378]: the blank bullet (bullet # 4) to be deleted.
>>>> * [Annex E.1.2, pg 378]: Bullet #3 and #5 to be merged into one.
>>>>
>>>> Annex G: Open issues
>>>> * Annex G to be deleted from the LRM.
>>>>
>>>> Annex H: Change history
>>>> * [Table H.4, pg 398]: Items 14 & 16 are duplicates. Stu to verify.
>>>> * [Table H.4, pg 398]: In item 17, cross/timer/above have an
>>>> additional
>>>> enable argument.
>>>> * [Table H.4, pg 398]: Items 33 and 34 can be merged into single item
>>>> * [Table H.4, pg 399]: Add new item saying "Annex G of LRM v2.2 has
>>>> been
>>>> deleted. Annex C of LRM v2.2 has been split and the section describing
>>>> the changes from previous LRM versions has been documented in this
>>>> Annexure (Annex H)."
>>>> * [clause H.1.1, pg 399]: Clause H.1.1 should become H.2
>>>>
>>>> Next Committee Meeting:
>>>> * Planned for Monday, May 19th 7am Pacific time
>>>> * Stu plans to release the next version of the document before the end
>>>> of this week. Stu will send across two versions, one with change bars
>>>> (to reflect the changes from today's meeting) and one without change
>>>> bars - the official draft4 version.
>>>> * Once all the changes are ratified by the committee, the clean LRM
>>>> v2.3
>>>> draft4 version will be submitted to the Accellera board from approval
>>>>
>>>> Regards,
>>>> Sri
>>>> --
>>>> Srikanth Chandrasekaran
>>>> Design Technology (Tools Development)
>>>> Freescale Semiconductor Inc.
>>>> T:+91-120-439 5000 p:x3824 f: x5199
>>>>
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