Re: [sv-bc] hex number in string literal

[Context and attribute lines restored manually]

Brad Pierce wrote:
 > Krishanu Debnath wrote:
 >> Hello,
 >>
 >> This has been discussed before(http://www.eda.org/sv-bc/hm/1539.html),
 >> But I
 >> still don't find the normative answer. Lets try again.
 >>
 >> Here is the Chapter & Verse(CV) from standard about special string
 >> character -
 >> hex number.
 >>
 >> 3.6 String literals
 >> [...]  SystemVerilog adds the following special string characters:
 >> \v vertical tab
 >> \f form feed
 >> \a bell
 >> \x02 hex number
 >>
 >> Sec 4.7 String data type shows an example of hex number in string
 >> literal.
 >>
 >> [page 20]
 >>
 >> bit [10:0] a = "\x41"; // assigns to a 'b000_0100_0001
 >>
 >> But It does not mandate about the number of hex digits required. is it 2?
 >>
 >> Please note that Verilog 2005 draft is very clear about how many
 >> characters
 >> are required to specify octal digits in string literal. Here is the CV
 >> from
 >> Verilog 2005 draft ...
 >>
 >> Sec 3.6.3 Special characters in strings
 >>
 >> \ddd A character specified in 1--3 octal digits (0 ? d ? 7).
 >>
 >> If less than three characters are used, the following character shall
 >> not be an
 >> octal digit. Implementations may issue an error if the character
 >> represented is
 >> greater than \377.
 >>
 >> Now consider this example: (note the embedded comments)
 >>
 >> module sample;
 >>
 >>     string s;
 >>
 >>     initial
 >>     begin
 >>         s = "\x41";  // this means now s is "A". ASCII value of A is
 >> 0x41.
 >>         $display("value of s %s \n", s);
 >>
 >>         s = "\x4142"; // does this mean s is "A42" ?
 >>         $display("value of s %s \n", s);
 >>
 >>         s = "\x41\x42"; // does this mean s is "AB" ?
 >>         $display("value of s %s \n", s);
 >>
 >>         s = "\x4"; // less than two characters followed by x, so it
 >> will be not
 >>                    // treated as hex number.
 >>         $display("value of s %s \n", s);
 >>     end
 >> endmodule
 >>
 >> Does the above make sense?
 >>
 >> Krishanu
 >
> For background on the V2005 clarification about octal escape sequences,
> see
> 
>    http://www.boyd.com/1364_btf/report/full_pr/119.html
> 
> -- Brad
> 

Umm, I just read it. But does it *answer* my question?

Krishanu