Ray, My comments inlined below. Arturo -----Original Message----- From: Ryan, Ray [mailto:Ray_Ryan@mentor.com] Sent: Thursday, May 18, 2006 11:43 AM To: Arturo Salz; Rich, Dave; Vreugdenhil, Gordon Cc: sv-ec@eda.org Subject: RE: [sv-ec] random resizing of associative array Arturo, If an associative array with integral indices can be resized and the indices become 0..N (N = size-1) what about the following: module top; typedef enum bit[7:0] { red= 1, teal= 2, blue= 4, aqua= 8, cyan=16, gold=32, pink=64, rust=128 } color; int assoc[color]; initial begin assert( randomize(assoc) with (assoc.size()==8;} ); ... end endmodule Note that "assoc[color'(3)] = 20;" is a legal assignment. So does the randomize create 8 entries with index values 0,1,2,3,4,5,6,7 ? [Arturo] I believe arrays indexed by enumerated types should not be resizable. Only plain integral types. My opinion is that resizing of an associative array is not defined in the current LRM. [Arturo] I agree that it is not well defined. - In section 13.3 where size constraints are introduced, they are only described for dynamic arrays. [Arturo] Yes. That's true. However, that description applies equally well to queues. - The size() method is not defined for associated arrays. So size constraints can't be specified (per LRM). [Arturo] Yes. That needs to be addressed. Dave had a proposal. - The semantics of resizing associative arrays is not described. [Arturo] Yes. I agree. Also, if randomize resizing of an associative array should be equivalent to using a dynamic array, why even add this as an enhancement? [Arturo] That's the whole point. We can either disallow it altogether (as you suggest) or do something reasonable for the common cases. I'd rather do that than have to explain why an associative array indexes by integers cannot be resized by constraints. - Ray > -----Original Message----- > From: Arturo Salz [mailto:Arturo.Salz@synopsys.com] > Sent: Wednesday, May 17, 2006 3:56 PM > To: Rich, Dave; Arturo Salz; Ryan, Ray; Vreugdenhil, Gordon > Cc: sv-ec@eda.org > Subject: RE: [sv-ec] random resizing of associative array > > Dave, > > I didn't imply you said that. I'm sorry if I left that impression. > > The index value IS a state variable because it must be a > literal constant. Only the foreach construct allows > non-literal indices. > > My point is that I did specify how the index value is set: > when an associative array isd resized, the indices become > 0..N (N = size-1). > And, it follows from that description that arrays of non > integral indices cannot be resized. > > Arturo > > -----Original Message----- > From: Rich, Dave [mailto:Dave_Rich@mentor.com] > Sent: Wednesday, May 17, 2006 3:13 PM > To: Arturo Salz; Ryan, Ray; Vreugdenhil, Gordon > Cc: sv-ec@eda.org > Subject: RE: [sv-ec] random resizing of associative array > > Arturo, > > I think we are in agreement, at least agree your example > should be legal. > > I didn't say that you couldn't use an AA in a constraint; I > just said the index value would be a state variable, i.e. not > randomized. > > If you were to allow re-sizing an AA, you'd have to specify > how the index value is to be set. > > Dave > > > > -----Original Message----- > > From: Arturo Salz [mailto:Arturo.Salz@synopsys.com] > > Sent: Wednesday, May 17, 2006 3:04 PM > > To: Rich, Dave; Ryan, Ray; Vreugdenhil, Gordon; Arturo Salz > > Cc: sv-ec@eda.org > > Subject: RE: [sv-ec] random resizing of associative array > > > > Dave, > > > > Disallowing associative arrays from participating in constraints as > > random variables is too restrictive. If users do not resize the > > associative array there is no ambiguity. Also, the LRM > already states > > that index expressions must be literal constants, so it's > not possible > > to randomize the indices. Consider the following: > > > > rand byte aa[int]; > > rand a, b; > > > > constraint x { foreach( aa, j ) { aa[j] inside { a, b }; } > > > > That is a perfectly good constraint. > > > > I believe the only erratum needed is to specify what > happens when the > > size of the associative array is constrained. My proposal is > > straightforward and I believe allows most useful situations without > > being unduly restrictive. > > > > Arturo > > > > -----Original Message----- > > From: Rich, Dave [mailto:Dave_Rich@mentor.com] > > Sent: Wednesday, May 17, 2006 2:35 PM > > To: Ryan, Ray; Vreugdenhil, Gordon; Arturo Salz > > Cc: sv-ec@eda.org > > Subject: RE: [sv-ec] random resizing of associative array > > > > I don't think this is the desired behavior, nor does the LRM even > > remotely suggest this. > > > > I would propose that we add an erratum explicitly saying that > > randomize() shall not re-size an associative array and > shall consider > > the size and keys as state variables. > > > > Dave > > > > > >Received on Thu May 18 12:07:08 2006
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