| Number | 308
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| Category | errata
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| Synopsis | 9.7.2 ambiguous about @r when r is a vector
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| State | lrmdraft
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| Class | errata-simple
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| Arrival-Date | Mar 23 2003
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| Originator | Shalom.Bresticker@motorola.com
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| Release | 2001b: 9.7.2
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| Environment |
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| Description |
9.7.2 is ambiguous about when "@r" is triggered when r is a vector. @(posedge r) and @(negedge r) trigger only on the LSB of r. But the LRM is ambiguous whether "@r" triggers on any change in r or only on a change in the LSB of r. To the best of my knowledge, all tools treat "@r" as triggering on any change in r. |
| Fix |
AS REVISED AND PASSED BY ETF ON 2004-11-01: In 9.7.2, CHANGE "If the expression evaluates to more than a 1-bit result, the edge transition shall be detected on the least significant bit of the result. The change of value in any of the operands without a change in the value of the least significant bit of the expression result shall not be detected as an edge." TO "An implicit event shall be detected on any change in the value of the expression. An edge event shall be detected only on the least significant bit of the expression. A change of value in any operand of the expression without a change in the result of the expression shall not be detected as an event." Also, in 9.7.7, DELETE "The event expression shall be resolved to a 1-bit value." |
| Audit-Trail |
From: Shalom.Bresticker@motorola.com To: etf-bugs@boyd.com Cc: Subject: Re: errata/308: 9.7.2 ambiguous about @r when r is a vector Date: Tue, 2 Sep 2003 12:34:34 +0300 (IDT) This should be combined with issue 88. Another place to correct is 9.7.7, para. 3, where it says that "The event expression shall be resolved to a 1-bit value." > 9.7.2 is ambiguous about when "@r" is triggered when r is a > vector. > > @(posedge r) and @(negedge r) trigger only on the LSB of r. > > But the LRM is ambiguous whether "@r" triggers on any change > in r or only on a change in the LSB of r. > > To the best of my knowledge, all tools treat "@r" as > triggering on any change in r. Shalom From: Shalom.Bresticker@freescale.com To: etf-bugs@boyd.com Cc: Subject: Re: errata/308: 9.7.2 ambiguous about @r when r is a vector Date: Fri, 29 Oct 2004 13:08:25 +0200 (IST) 9.7.2 says, "The value changes on nets and variables can be used as events to trigger the execution of a statement. This is known as detecting an implicit event. The event can also be based on the direction of the change ... The behavior of posedge and negedge is shown in Table 9-1 and can be described as follows. -- A negedge ... -- A posedge ... If the expression evaluates to more than a 1-bit result, the edge transition shall be detected on the least significant bit of the result." PROPOSAL: Change the last sentence quoted above to: "If the expression evaluates to more than a 1-bit result, an implicit event shall be detected on a value change of any bit of the result. An edge event shall be detected only on the least significant bit of the result." Shalom On Sun, 23 Mar 2003, Shalom Bresticker wrote: > 9.7.2 is ambiguous about when "@r" is triggered when r is a > vector. > > @(posedge r) and @(negedge r) trigger only on the LSB of r. > > But the LRM is ambiguous whether "@r" triggers on any change > in r or only on a change in the LSB of r. > > To the best of my knowledge, all tools treat "@r" as > triggering on any change in r. -- 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 Fix replaced by Shalom.Bresticker@freescale.com on Sun Oct 31 01:58:11 2004 In 9.7.2, CHANGE "If the expression evaluates to more than a 1-bit result, the edge transition shall be detected on the least significant bit of the result." TO "If the expression evaluates to more than a 1-bit result, an implicit event shall be detected on a value change of any bit of the result. An edge event shall be detected only on the least significant bit of the result." Also, in 9.7.3, DELETE "The event expression shall be resolved to a 1-bit value." From: Shalom.Bresticker@freescale.com To: Neil Korpusik <Neil.Korpusik@Sun.COM> Cc: etf-bugs@boyd.com Subject: Re: errata/308: PROPOSAL - 9.7.2 ambiguous about @r when r is a vector Date: Tue, 2 Nov 2004 05:58:35 +0200 (IST) Yes, thanks. Shalom On Mon, 1 Nov 2004, Neil Korpusik wrote: > Instead of referring to 9.7.3, I assume that you meant to refer to 9.7.7 > in your second modification listed below. > > > > Also, in 9.7.3, > > > > DELETE > > > > "The event expression shall be resolved to a 1-bit value." > > > > > > http://boydtechinc.com/cgi-bin/issueproposal.pl?cmd=view&database=default&pr=308 -- 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 Fix replaced by Shalom.Bresticker@freescale.com on Tue Nov 2 07:24:13 2004 AS REVISED AND PASSED BY ETF ON 2004-11-01: In 9.7.2, CHANGE "If the expression evaluates to more than a 1-bit result, the edge transition shall be detected on the least significant bit of the result. The change of value in any of the operands without a change in the value of the least significant bit of the expression result shall not be detected as an edge." TO "An implicit event shall be detected on any change in the value of the expression. An edge event shall be detected only on the least significant bit of the expression. A change of value in any operand of the expression without a change in the result of the expression shall not be detected as an event." Also, in 9.7.7, DELETE "The event expression shall be resolved to a 1-bit value." |
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