> I believe what you say about the initial value of w being 1'bz. > But what does the sentence [mean] > Nets with drivers shall assume the output value of their drivers. I think I can weasel my way out of that one... Before time 0, the driver doesn't yet have an output value because its input has not yet propagated to its output. However, this goes back to what I asked in an earlier post... > Or is this too mechanistic a view of continuous assignment? The truth is that this is a corner case that needs specific definition, because it will never be really obvious and it is likely to be at the mercy of tool implementation differences unless it's defined as a special case. Personally I would have thought that defining the time-0 Preponed value of all nets to be 'z would be wise, because it will make sense not only for nets with simple zero-delay drivers but also for drivers with delays, and nets that are truly undriven. -- Jonathan Bromley, Consultant DOULOS - Developing Design Know-how VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services Doulos Ltd. Church Hatch, 22 Market Place, Ringwood, Hampshire, BH24 1AW, UK Tel: +44 (0)1425 471223 Email: jonathan.bromley@doulos.com Fax: +44 (0)1425 471573 Web: http://www.doulos.com The contents of this message may contain personal views which are not the views of Doulos Ltd., unless specifically stated. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.Received on Tue Nov 20 06:52:58 2007
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