| Number | 622
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| Notify-List |
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| Category | errata
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| Synopsis | Return value for left/right range of unsize parameter
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| State | ptfpassed
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| Class | errata-ptf
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| Arrival-Date | Sep 16 2004
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| Originator | James H. Vellenga
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| Release |
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| Description |
Our users, in order to be able to do range checking on parameter indexing and bit selects, want to be able to know the bounds for parameters, whether or not the parameter has an explicitly declared range. The specification does not say what should happen if an application attempts to access the left or right range of a parameter when the parameter does not have ranges specified in the HDL. To allow users to distinguish the two forms of declaration, we propose that VPI return NULL handles for left and right ranges of unsized parameters without reporting an error. Proposal: In section 26.6.12, "Parameter, specparam", add the following note: 3) If a parameter does not have an explicitly declared range, vpiLeftRange and vpiRightRange shall return a NULL handle. James H. Vellenga Cadence Design Systems, Inc. |
| Fix |
This has been resolved via: http://www.eda.org/svdb/bug_view_page.php?bug_id=0000309 |
| Audit-Trail |
From: Shalom.Bresticker@freescale.com To: vellenga@cadence.com Cc: ptf-bugs@boyd.com Subject: Re: errata/622: Return value for left/right range of unsize parameter Date: Sun, 19 Sep 2004 15:35:01 +0300 (IDT) 3.11.1 says, "A parameter with no range specification, and with either a signed type specification or no type specification, shall have an implied range with an lsb equal to 0 and an msb equal to one less than the size of the final value assigned to the parameter. "A parameter with no range specification, and with either a signed type specification or no type specification, and for which the final value assigned to it is unsized, shall have an implied range with an lsb equal to 0 and an msb equal to an implementation-dependent value of at least 31." > Our users, in order to be able to do range checking on parameter > indexing and bit selects, want to be able to know the bounds for > parameters, whether or not the parameter has an explicitly declared > range. The specification does not say what should happen if an > application attempts to access the left or right range of a parameter > when the parameter does not have ranges specified in the HDL. Shalom -- Shalom Bresticker Shalom.Bresticker @freescale.com Design & Verification Methodology Tel: +972 9 9522268 Freescale Semiconductor Israel, Ltd. Fax: +972 9 9522890 POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 5441478 [ ]Freescale Internal Use Only [ ]Freescale Confidential Proprietary From: "Jim Vellenga" <vellenga@cadence.com> To: <Shalom.Bresticker@freescale.com> Cc: <ptf-bugs@boyd.com> Subject: RE: errata/622: Return value for left/right range of unsize parameter Date: Mon, 20 Sep 2004 08:47:20 -0400 Thank you, Shalom. As you have observed, a parameter that has no range specification does indeed have implicit left and right range values. So an alternative would be to have the vpiLeftRange and vpiRightRange relationships return the implicit values. The one advantage to having vpiLeftRange and vpiRightRange return NULL handles is that this allows the user to determine whether or not the parameter does have a range specification. This could be useful, for example, in a decompiler application. This is the reason that I favored having these relations return NULL handles. For a parameter that has no range specification, the user can still use the vpiSize property to determine the left and right range values, so there is no loss of information. Regards, James H. Vellenga Cadence Design Systems, Inc. --------------------------------------------------------- James H. Vellenga 978-262-6381 Engineering Director (FAX) 978-262-6636 Cadence Design Systems, Inc. vellenga@cadence.com 270 Billerica Rd Chelmsford, MA 01824-4179 "We all work with partial information." ---------------------------------------------------------- From: Shalom.Bresticker@freescale.com To: Jim Vellenga <vellenga@cadence.com> Cc: ptf-bugs@boyd.com Subject: RE: errata/622: Return value for left/right range of unsize parameter Date: Mon, 20 Sep 2004 22:38:09 +0300 (IDT) What is done for integer variables? They also have an implicit range. -- Shalom Bresticker Shalom.Bresticker @freescale.com Design & Verification Methodology Tel: +972 9 9522268 Freescale Semiconductor Israel, Ltd. Fax: +972 9 9522890 POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 5441478 From: "Jim Vellenga" <vellenga@cadence.com> To: <Shalom.Bresticker@freescale.com> Cc: <ptf-bugs@boyd.com> Subject: RE: errata/622: Return value for left/right range of unsize parameter Date: Mon, 20 Sep 2004 15:51:28 -0400 The notes in section 26.6.8 say that vpiLeftRange and vpiRightRange apply to variables when and only when vpiArray is TRUE (Note 5). Note 3 says that vpiArray is TRUE if and only if the variable handle references and array of variables. So a single variable (integer, time, or real) that is not part of an array does not have a vpiLeftRange or a vpiRightRange. But in this case, it is also an error to return a vpiLeftRange or vpiRightRange. These relations do not return a NULL handle for a non-array variable. Regards, Jim V. --------------------------------------------------------- James H. Vellenga 978-262-6381 Engineering Director (FAX) 978-262-6636 Cadence Design Systems, Inc. vellenga@cadence.com 270 Billerica Rd Chelmsford, MA 01824-4179 "We all work with partial information." ---------------------------------------------------------- ] -----Original Message----- ] From: shalom@eagle.msil.sps.mot.com ] [mailto:shalom@eagle.msil.sps.mot.com] On Behalf Of ] Shalom.Bresticker@freescale.com ] Sent: Monday, September 20, 2004 3:38 PM ] To: Jim Vellenga ] Cc: ptf-bugs@boyd.com ] Subject: RE: errata/622: Return value for left/right range of ] unsize parameter ] ] What is done for integer variables? ] ] They also have an implicit range. ] ] -- ] Shalom Bresticker Shalom.Bresticker ] @freescale.com ] Design & Verification Methodology Tel: ] +972 9 9522268 ] Freescale Semiconductor Israel, Ltd. Fax: ] +972 9 9522890 ] POB 2208, Herzlia 46120, ISRAEL Cell: ] +972 50 5441478 ] ] ] Fix replaced by chas@cadence.com on Thu Mar 17 10:06:29 2005 This has been resolved via: http://www.eda.org/svdb/bug_view_page.php?bug_id=0000309 |
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