Subject: RE: [sv-ec] Asychronous mailbox proposal
From: Kevin Cameron x3251 (Kevin.Cameron@nsc.com)
Date: Thu Dec 12 2002 - 16:41:12 PST
> From: "David W. Smith" <david.smith@synopsys.com>
>
> Hi Kevin,
> I would request that any additions like this go through me before going to
> Stu. I believe there may be some problems with what you suggest and would
> prefer to have the discussion first.
>
> Stu, please wait on adding this.
>
> Regards
> David
>
> David W. Smith
> Synopsys Scientist
Since it's only a small extension to mailbox functionality, can we clear up
any issues with it over the reflector?
BTW, when was striking out dynamic processes approved?
Kev.
> -----Original Message-----
> From: owner-sv-ec@eda.org [mailto:owner-sv-ec@eda.org] On Behalf Of Kevin Cameron
> Sent: Thursday, December 12, 2002 12:30 PM
> To: Stuart Sutherland
> Cc: sv-ec
> Subject: [sv-ec] Asychronous mailbox proposal
>
>
> Stu,
>
> I was wondering if you could paste the section below into the LRM for review
> with the mailbox stuff, it's the only functionality from the channels
> proposal that isn't handled by mailboxes (the rest is handled by DirectC):
>
> 12.5.1 Asynchronous Mailbox Communication
>
> Data arriving at a mailbox generates an event. The event is true while data
> remains in the mailbox. As with signal events these events can be waited for
> with the @ operator. The following code could be used to replace a wire of
> type logic with a FIFO to safely cross clock domains:
>
> typedef mailbox #(logic) l_mbox;
>
> l_mbox lm = new;
>
> logic l_val1;
> always @(posedge clock1) lm.put(l_val1) // write data on clock1
>
> logic l_val2;
> always @(lm && posedge clock2) lm.get(l_val2); // sync data to
> clock2
>
> -------------------------------------------
>
>
> Note: the alternative code without @(lm) would poll on every "posedge
> clock2" and do a try_get - which is a lot more inefficient.
>
> Regards,
> Kev.
>
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> National Semiconductor, Tel: (408) 721 3251
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>
>
>
>
>
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