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

From: Geoffrey.Coram <geoffrey.coram_at_.....>
Date: Wed May 21 2008 - 11:32:01 PDT
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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> 
> 

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