| Number | 73
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| Category | errata
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| Synopsis | 4.1.14 implies replication legal lvalue
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| State | lrmdraft
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| Class | errata-discuss
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| Arrival-Date | Jul 16 2002
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| Originator | sharp@cadence.com
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| Release | 2001b: 4.1.14
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| Environment |
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| Description |
Section 4.1.14 describes the behavior of concatenations when used in expressions (i.e. rvalues). It also describes replications as a form of concatenation, and the comments on the examples give concatenations that they are equivalent to. Concatenations are also allowed as lvalues, such as on the left-hand-side of assignments or attached to output ports. The statement that replication is equivalent to some concatenation can be interpreted to mean that replication is also legal as an lvalue. This was never the intent, and certainly is not true in Verilog-XL. |
| Fix |
In 4.1.14, CHANGE "Another form of concatenation is the replication operation. The first expression shall be a non-zero, non-X and non-Z constant expression, the second follows the rules for concatenation." TO "An operator that can be applied only to concatenations is replication, which is expressed by a concatenation preceded by a positive, non-X and non-Z constant expression, enclosed together within brace characters, and which indicates a joining together of that many copies of the concatenation. Unlike regular concatenations, expressions containing replications shall not appear on the left-hand side of an assignment and shall not be connected to output or inout ports." and in the example that follows these sentences, CHANGE "// This is equivalent to" TO "// This yields the same value as" and in the final example of 4.1.14, CHANGE "nested concatenations" TO "a replication nested within a concatenation" and CHANGE "// This is equivalent to" TO "// This yields the same value as" |
| Audit-Trail |
From: Shalom Bresticker <Shalom.Bresticker@motorola.com> To: Brad.Pierce@synopsys.com Cc: etf-bugs@boyd.com Subject: Re: errata/73: PROPOSAL - 4.1.14 implies replication legal lvalue Date: Mon, 22 Sep 2003 12:07:35 +0300 A few quibbles: Brad.Pierce@synopsys.com wrote: > In 4.1.4, 4.1.14 > CHANGE > > "Another form of concatenation is the replication > operation. The first expression shall be a non-zero, > non-X and non-Z constant expression, the second > follows the rules for concatenation." > > TO > > "An operator that can be applied only to concatenations > is replication, which is expressed by a concatenation > preceded by a nonzero, non-X and non-Z constant Should be "positive" instead of "nonzero". See #76. > expression, enclosed together within brace > characters, and which indicates a joining together > of that many copies of the concatenation. Unlike > true concatenations, including nested concatenations, What is a "true" concatentation? Maybe "regular" concatenations, instead? "nested concatenations" have not been mentioned yet. > expressions containing replications can neither > be assigned to nor connected to output or inout > ports." Sounds like it says, "can neither be assigned to output or inout ports nor .." How about something like "shall not appear on the left-hand size of an assignment"? (Note that the language should be "shall not" instead of "can not".) The rest looks OK. Shalom -- Shalom Bresticker Shalom.Bresticker@motorola.com Design & Reuse Methodology Tel: +972 9 9522268 Motorola Semiconductor Israel, Ltd. Fax: +972 9 9522890 POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 441478 From: Steven Sharp <sharp@cadence.com> To: etf-bugs@boyd.com, Brad.Pierce@synopsys.com Cc: Subject: Re: errata/73: PROPOSAL - 4.1.14 implies replication legal lvalue Date: Mon, 6 Oct 2003 21:24:51 -0400 (EDT) I have now reviewed Brad's proposal, and I think it makes the situation clear. It does not list all of the possible lvalue situations where a replication would not be allowed, but a full list would probably cause more confusion than it prevented. The longer comment text might cause some formatting problems. We could use something shorter but less clear, like "// Same value as", or let the editor worry about it. Steven Sharp sharp@cadence.com From: Shalom Bresticker <Shalom.Bresticker@motorola.com> To: Steven Sharp <sharp@cadence.com> Cc: etf-bugs@boyd.com Subject: Re: errata/73: PROPOSAL - 4.1.14 implies replication legal lvalue Date: Thu, 09 Oct 2003 12:00:00 +0200 Let the soon-to-be-spun-off editor worry about it. Steven Sharp wrote: > I have now reviewed Brad's proposal, and I think it makes the situation clear. > It does not list all of the possible lvalue situations where a replication > would not be allowed, but a full list would probably cause more confusion > than it prevented. The longer comment text might cause some formatting > problems. We could use something shorter but less clear, like > "// Same value as", or let the editor worry about it. -- Shalom Bresticker Shalom.Bresticker@motorola.com Design & Reuse Methodology Tel: +972 9 9522268 Motorola Semiconductor Israel, Ltd. Fax: +972 9 9522890 POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 441478 |
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