RE: [sv-ec] Comments on 890-5.pdf

From: Jonathan Bromley <jonathan.bromley_at_.....>
Date: Tue Feb 13 2007 - 07:54:00 PST
Stuart wrote:

> My understanding has always been that for # unit delays, a 
> negative delay value is treated as an unsigned value. 
> I also thought that was in the 1364 LRM, somewhere.

It is; a colleague has pointed out to me that 1364-2005
clause 9.7.1 clearly states that the value is sign-extended
to the width of "time" and then treated as unsigned.  So
the simulator that treated the negative value as being zero
was definitely violating 1364-2005.

64-bit "-1" treated as unsigned is an awful long time even
if it's in picoseconds, and if it's counting cycles
of a clock we're likely to be some way into 
heat-death-of-universe territory.  Seems to me
that stipulating a negative-delay warning for 
both ## and # would be a very good idea.
-- 
Jonathan Bromley, Consultant

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Received on Tue Feb 13 07:54:26 2007

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