Date: Mon May 28 2007 - 06:01:02 PDT
Chris, Thanks. I understand what you wrote and agree. My problem is that while the LRM says that elsewhere, as I myself quoted, if you add the statement, "Unsized unsigned literal constants where the high-order bit is unknown (X or x) or three-state (Z or z) shall be extended to the size of the expression containing the literal constant," it does not say that here. x is not the same as 'hx. "x" could be misinterpreted to mean 'x, which is different from 'hx. And if "x" means 'hx here, then the statement seems redundant as the behavior statement is already stated previously. Thanks, Shalom ________________________________ From: Chris Spear [mailto:Chris.Spear@synopsys.com] Sent: Monday, May 28, 2007 3:49 PM To: Bresticker, Shalom; sv-bc@eda.org Subject: RE: [sv-bc] D3 5.7.1: default length of x/z Shalom, 'hz and 'hx are treated as 32-bit numbers. But unlike 'h0 and 'h1, the z or x values are extended into the upper bits. So 'hz is equivalent to 32'hZZZZ_ZZZZ and 32'hx is equivalent to 32'hXXXX_XXXX. /********************************************************* Chris Spear Verification Specialist Synopsys, Inc. Phone 508-263-8114 .. __@ 377 Simarano Drive Fax 508-263-8123 _`\<,_ Marlboro, MA 01752 USA Cell 508-254-7223 .. (*)/ (*) Spear_ f rom _Synopsys.com http://Chris.Spear.net/systemverilog <http://Chris.Spear.net/systemverilog> *********************************************************/ ________________________________ From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Bresticker, Shalom Sent: Monday, May 28, 2007 4:51 AM To: sv-bc@eda.org Subject: [sv-bc] D3 5.7.1: default length of x/z Hi, In Draft 3, 5.7.1 says, "The default length of x and z is the same as the default length of an integer." This sentence goes back to 1364. My question is, what is meant by "x and z" here? x and z, unlike a simple integer like "3", cannot appear in the simple forms "x" and "z". Then they would be treated as identifiers, data object names. Is it referring to forms like 'hx, 'bz? If so, we already have a sentence that says, "The number of bits that make up an unsized number (which is a simple decimal number or a number with a base specifier but no size specification) shall be at least 32." The sentence is currently misleading as it could refer to forms like 'x, which when self-determined is 1 bit, not 32 bits. Also, the word "integer" in the sentence is also ambiguous, as there are many types of integers. For example, 1'b0 is also an integer. It is a sized integer constant. Shalom Shalom Bresticker Intel Jerusalem LAD DA +972 2 589-6852 +972 54 721-1033 -- This message has been scanned for viruses and dangerous content by MailScanner <http://www.mailscanner.info/> , and is believed to be clean. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
