Re: errata/308: 9.7.2 ambiguous about @r when r is a vector

From: Shalom.Bresticker@freescale.com
Date: Fri Oct 29 2004 - 04:00:00 PDT

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    The following reply was made to PR errata/308; it has been noted by GNATS.

    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.
     
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     Shalom Bresticker Shalom.Bresticker @freescale.com
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