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Honored ContributorHow about a verilog case statement that covers a range?
How about a verilog case statement that covers a range?
e.g. : case(xcount) begin 1-100 : junk<=1; 101 : junk<=2; 102-200 : junk<=3; endcaseForum Discussion
6 Replies
Altera_ForumSystemVerilog has it using the inside operator
Another nice thing about the case inside statement is that it uses asymmetric wildcard matching.case (xcount) inside : junk<=1; 101 : junk<=2; : junk<=3; endcase
That means don't cares only match on the case item, not the selecting expression. So if xcode == 3'bx01, the default branch would be taken, not the first branch.case (xcode) inside 3'b00? : junk<=1; 3'b0?0 : junk<=2; 3'b?00 : junk<=3; default: junk <='x; endcase- Altera_Forum--- Quote Start --- SystemVerilog has it using the inside operator
Another nice thing about the case inside statement is that it uses asymmetric wildcard matching.case (xcount) inside : junk<=1; 101 : junk<=2; : junk<=3; endcase
That means don't cares only match on the case item, not the selecting expression. So if xcode == 3'bx01, the default branch would be taken, not the first branch. --- Quote End --- Thanks very much. But I think this "inside" only for SystemVerilog, right?case (xcode) inside 3'b00? : junk<=1; 3'b0?0 : junk<=2; 3'b?00 : junk<=3; default: junk <='x; endcase - Altera_Forum
Yes. Hopefully if more people ask for it, it will become more widely supported.
To code this in Verilog, you could create an in-between function or macrofunction reg inbetween(input low, value, high); begin inbetween = value >= low && value <= high; end endfunction case (1); inbetween(1,xcount,100): junk<=1; inbetween(101,xcount,101): junk<=2; inbetween(102,xcount,200): junk<=3; endcase - Altera_Forum--- Quote Start --- Yes. Hopefully if more people ask for it, it will become more widely supported. To code this in Verilog, you could create an in-between function or macro
--- Quote End --- Thanks dave. Yes, I think this is very good idea. And this should be able to be synthesized, right?function reg inbetween(input low, value, high); begin inbetween = value >= low && value <= high; end endfunction case (1); inbetween(1,xcount,100): junk<=1; inbetween(101,xcount,101): junk<=2; inbetween(102,xcount,200): junk<=3; endcase - Altera_Forum--- Quote Start --- SystemVerilog has it using the inside operator
Another nice thing about the case inside statement is that it uses asymmetric wildcard matching.case (xcount) inside : junk<=1; 101 : junk<=2; : junk<=3; endcase
That means don't cares only match on the case item, not the selecting expression. So if xcode == 3'bx01, the default branch would be taken, not the first branch. --- Quote End --- I added this syntax to an existing SystemVerilog design, but Quartus choked on the "inside" keyword when I tried to build. It's a little ironic, because the Quartus text editor recognizes it as a key word (it shows up in blue). Am I correct in saying that Quartus does not support "case inside"? I do not see it mentioned in the Quartus SV Support documentation.case (xcode) inside 3'b00? : junk<=1; 3'b0?0 : junk<=2; 3'b?00 : junk<=3; default: junk <='x; endcase - Altera_Forum
It is very easy to recognize a list of keywords to prevent people from using them as identifiers. Supporting the functionality behind them is another story.
