RE: [sv-ec] Mantis 1067 proposal uploaded

I like the proposal, but I have a few comments:

1. Table 7-1 should move from 7.8.6, which is specific to associative arrays, to 7.4.6 (Indexing and slicing of arrays), which is general.

2. The proposal distinguishes between unpacked arrays, saying that they return the value shown in Table 7-1, and bit-selects/part-selects, that return x for 4-state values and 0 for 2-state values. I think the wording in the proposal leaves unclarified cases of multiple packed dimensions, where there is an x/z or out-of-bounds index in a packed dimensions that is not the least significant dimension.

3. If Table 7-1 is going to have special entries for variable-size arrays and for fixed-size arrays, then what about structs and unions? Table 6-7 does not have special entries for arrays.

4. In 7.10.1, the proposal changes "with X's or Z's" to "has one or more X or Z bits". The latter should be colored blue.

5. 11.5.1 contains, "or the bit-select is x or z". This should probably be changed to "or any bit of the bit-select is x or z", to be more precise and more consistent with other places. This paragraph, describing bit-selects, should also say what happens if such a bit-select is written as well as read.

6. There is also another paragraph in 11.5.1 that needs to be modified:

"A part-select that addresses a range of bits that are completely out of the address bounds of the vector, packed array, packed structure, parameter or concatenation, or a part-select that is x or z shall yield the value x when read and shall have no effect on the data stored when written. Part-selects that are partially out of range shall, when read, return x for the bits that are out of range and shall, when written, only affect the bits that are in range."

7. Some changes in the proposal delete the word "address", as in 11.5.1. In 11.5.2, the word remains. Is that deliberate?

8. 7.9.11 says, "If a default value is specified, then reading a nonexistent element shall yield the specified default value, and no warning shall be issued. Otherwise, the default initial value as described in Table 7-1 shall be returned."

However, Table 7-1 does not describe default initial values, certainly not after this proposal.

Regards,
Shalom

> -----Original Message-----
> From: owner-sv-ec@eda.org [mailto:owner-sv-ec@eda.org] On Behalf Of
> Jonathan Bromley
> Sent: Monday, March 14, 2011 2:01 AM
> To: sv-ec@eda.org
> Subject: [sv-ec] Mantis 1067 proposal uploaded
>
> hi EC,
>
> I've uploaded a draft proposal for 1067 (LRM consistency issues
> regarding access to nonexistent array elements). There are a
> couple of non-trivial issues involved and I'd be grateful if
> we could take a look at it soon.
>
> I had intended to do this a long while ago, but vacation and
> DVCon preparation got in the way. It may be better to delay
> discussion to the March-28 meeting to give people time to look
> at it more carefully.
>
> Thanks
> --
> Jonathan Bromley

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