| Number | 554
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| Category | errata
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| Synopsis | A.2.6: function_declaration BNF bug for return type declarations
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| State | lrmdraft
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| Class | errata-discuss
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| Arrival-Date | Mar 03 2004
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| Originator | "Brad Pierce" <Brad.Pierce@synopsys.com>
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| Release | 2001b: 10.3.1, A.2.6
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| Description |
In function_declaration, the BNF for the return type does not match the apparent intent. I would have expected the possible function return type declarations to be like those in a tf_output_declaration, which allows [ reg ] [ signed ] [ range ] and task_port_type where a task_port_type is integer, real, realtime or time. The function_declaration BNF, however, also allows the following additional weird function return type declarations signed integer signed real signed realtime signed time (and doesn't allow 'reg' before the implicit declaration). But integer, real and realtime are already signed, so the only return type this actually adds is 'signed time', which was probably not the intent. So, in my opinion, the BNF has a bug and should instead be allowing function return type declarations that are either exactly the same as allowed by tf_output_declaration or exacly those minus the optional 'reg'. (For more on the optional 'reg', see issue 452.) Personally, 'exactly the same' seems like the way to go. -- Brad |
| Fix |
In Syntax 1-3 and in A.2.6, in "function_declaration", CHANGE in 2 places [ signed ] [ range_or_type ] TO [ function_range_or_type ] CHANGE range_or_type ::= range | integer | real | realtime | time TO function_range_or_type ::= [ signed ] [ range ] | integer | real | realtime | time In 10.3.1, CHANGE the following paragraph "A function definition shall begin with the keyword function, followed by the optional keyword automatic, followed by the optional signed designator, followed by the range or type of the return value from the function, followed by the name of the function, and then either a semicolon, or a function port list enclosed in parenthesis, and then a semicolon, and then shall end with the keyword endfunction. The use of a range_or_type shall be optional. A function specified without a range or type defaults to a one bit reg for the return value. If used, range_or_type shall specify the return value of the function is a real, an integer, a time, a realtime or a value with a range of [n:m] bits. A function shall have at least one input declared." TO "A function definition shall begin with the keyword function, followed by the optional keyword automatic, followed by an optional function_range_or_type of the return value from the function, followed by the name of the function, and then either a semicolon, or a function port list enclosed in parenthesis, and then a semicolon, and then shall end with the keyword endfunction. The use of a function_range_or_type shall be optional. A function specified without a function_range_or_type shall default to a scalar for the return value. If used, function_range_or_type shall specify that the return value of the function is a real, an integer, a time, a realtime, or a vector (optionally signed) with a range of [n:m] bits. A function shall have at least one input declared." CLOSE issue #607 as a duplicate of #554. |
| Audit-Trail |
From: Shalom.Bresticker@motorola.com To: etf-bugs@boyd.com Cc: Subject: Re: errata/554: A.2.6: function_declaration BNF bug for return type declarations Date: Thu, 4 Mar 2004 10:29:23 +0200 (IST) Brad, You are clearly correct that the BNF is too lenient here. I would guess that it occurs in order not to complicate function_declaration too much. You should also compare it to parameter_declaration and see the discussion in 483 as well. Shalom > In function_declaration, the BNF for the return type does > not match the apparent intent. I would have expected the > possible function return type declarations to be like > those in a tf_output_declaration, which allows > > [ reg ] [ signed ] [ range ] > > and > task_port_type > > where a task_port_type is integer, real, realtime or time. > > The function_declaration BNF, however, also allows the following > additional weird function return type declarations > > signed integer > signed real > signed realtime > signed time > > (and doesn't allow 'reg' before the implicit declaration). > But integer, real and realtime are already signed, so > the only return type this actually adds is 'signed time', > which was probably not the intent. > > So, in my opinion, the BNF has a bug and should instead > be allowing function return type declarations that are > either exactly the same as allowed by tf_output_declaration > or exacly those minus the optional 'reg'. (For more on the > optional 'reg', see issue 452.) Personally, 'exactly the same' > seems like the way to go. -- 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 [x]Motorola General Business Information [ ]Motorola Internal Use Only [ ]Motorola Confidential Proprietary Fix replaced by Shalom.Bresticker@freescale.com on Sun Aug 1 08:04:01 2004 In Syntax 1-3 and in A.2.6, in "function_declaration", CHANGE in 2 places [ signed ] [ range_or_type ] TO [ function_range_or_type ] CHANGE range_or_type ::= range | integer | real | realtime | time TO function_range_or_type ::= [ signed ] [ range ] | integer | real | realtime | time In 10.3.1, CHANGE the following paragraph "A function definition shall begin with the keyword function, followed by the optional keyword automatic, followed by the optional signed designator, followed by the range or type of the return value from the function, followed by the name of the function, and then either a semicolon, or a function port list enclosed in parenthesis, and then a semicolon, and then shall end with the keyword endfunction. The use of a range_or_type shall be optional. A function specified without a range or type defaults to a one bit reg for the return value. If used, range_or_type shall specify the return value of the function is a real, an integer, a time, a realtime or a value with a range of [n:m] bits. A function shall have at least one input declared." TO "A function definition shall begin with the keyword function, followed by the optional keyword automatic, followed by an optional function_range_or_type of the return value from the function, followed by the name of the function, and then either a semicolon, or a function port list enclosed in parenthesis, and then a semicolon, and then shall end with the keyword endfunction. The use of a function_range_or_type shall be optional. A function specified without a function_range_or_type shall default to a one bit reg for the return value. If used, function_range_or_type shall specify that the return value of the function is a real, an integer, a time, a realtime, or a vector (optionally signed) with a range of [n:m] bits. A function shall have at least one input declared." CLOSE issue #607 as a duplicate of #554. Fix replaced by pieper@synopsys.com on Mon Aug 23 09:34:52 2004 In Syntax 1-3 and in A.2.6, in "function_declaration", CHANGE in 2 places [ signed ] [ range_or_type ] TO [ function_range_or_type ] CHANGE range_or_type ::= range | integer | real | realtime | time TO function_range_or_type ::= [ signed ] [ range ] | integer | real | realtime | time In 10.3.1, CHANGE the following paragraph "A function definition shall begin with the keyword function, followed by the optional keyword automatic, followed by the optional signed designator, followed by the range or type of the return value from the function, followed by the name of the function, and then either a semicolon, or a function port list enclosed in parenthesis, and then a semicolon, and then shall end with the keyword endfunction. The use of a range_or_type shall be optional. A function specified without a range or type defaults to a one bit reg for the return value. If used, range_or_type shall specify the return value of the function is a real, an integer, a time, a realtime or a value with a range of [n:m] bits. A function shall have at least one input declared." TO "A function definition shall begin with the keyword function, followed by the optional keyword automatic, followed by an optional function_range_or_type of the return value from the function, followed by the name of the function, and then either a semicolon, or a function port list enclosed in parenthesis, and then a semicolon, and then shall end with the keyword endfunction. The use of a function_range_or_type shall be optional. A function specified without a function_range_or_type shall default to a scalar for the return value. If used, function_range_or_type shall specify that the return value of the function is a real, an integer, a time, a realtime, or a vector (optionally signed) with a range of [n:m] bits. A function shall have at least one input declared." CLOSE issue #607 as a duplicate of #554. |
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