At 09:03 AM 2/12/99 -0500, Eric Scheirer wrote:
>Hi Giorgio,
>
>Yes, you are correct here. I thought that the standard specified
>that k-rate executions are atomic, but now I see that this is not
>the case. I think that this is the right answer: to make it
>clear that k-rate executions cannot be parallelized.
>
>I think the major benefit of SIMD implementation comes in the
>a-rate computations (since there's much more of it in typical
>instruments). So it is not such a loss to force the k-rate
>instances to be executed sequentially. Would you agree?
>
Yes, since k-rate code must be executed strictly before a-rate code.
I didn't think about separating k-code and a-code of the same
instance, but I agree that it is feasible at low cost.
>If so, it requires only a small corrigendum. A good place for
>it is list item 10 of Subclause 7.3.3.6 in my copy of the FDIS
>("Decoder execution while streaming" -- clause numbers are still
>changing, so it's hard to refer to them properly at the moment).
>Just to say the following:
>
> The executions of the various instrument instances at the k-rate
> shall be performed as atomic operations; that is, one must
> complete strictly before the next begins. This restriction is
> not placed on a-rate executions of instruments.
>
>fixes the problem, I think. It costs a small bit of efficiency,
>but allows the proper semantics of inter-instance communication
>with global variables.
>
>Please tell me your opinion on this.
>
As I said it is fine with me. Probably this solution has the best ratio
benefit/amount-of-change, since it does not modify anything in the
semantics of SA and make the decoding process more clear (and of
course my problem solvable :-)).
Thanks and best regards,
Giorgio
__________________________________________________________________
Giorgio ZOIA
Integrated Systems Center - DE/c3i - EPFL
CH-1015 Lausanne - SWITZERLAND
Phone: + 41 21 693 69 79 E-mail: Giorgio.Zoia@epfl.ch
Fax: +41 21 693 46 63
__________________________________________________________________
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