I
also think 2’b11 is correct. My reasoning is as
follows. (page numbers quoted below
based
on 1800-2009 LRM)
1)
An
unsized literal should at least contain 32 bits (page 37 of
LRM)
2)
All
bits of the unsized value shall be set to the value of the
specified bit. (page 37 of LRM)
So
in this example, the actual is at least 32bits wide with
value of “1111…..111”, while the
formal
is 2-bits wide.
In
my opinion, a warning would be nice, but I am not sure if LRM
requires this because of
the
unsized nature of the constant.
Thanks
Logie
Hello Shalom,
Questa 6.6b display 2'b11.
-dhiRAj
Bresticker, Shalom wrote:
The
conclusion of that thread seemed to be that 2'b11 would be the correct
answer
here.
Shalom
Hi Dhiraj,
I don't agree, I did not get anything explicit in LRM supporting your
answer.
We have already discussed about that in past. See the mail thread with
subject
"Query about '1" around early July 2008 time frame.
Regards
Surya
-------- Original Message --------
Subject: Re:[sv-bc] unsized number literals
From: Dhiraj Kumar Prasad <dhiraj@cal.interrasystems.com>
To: Bresticker, Shalom <shalom.bresticker@intel.com>
Cc: "sv-bc@eda.org"
<sv-bc@eda.org>,
Dhiraj Kumar Prasad <dhiraj@cal.interrasystems.com>
Date: Wednesday, August 04, 2010 5:09:57 PM
Hello Shalom,
The correct behavior should be 2'b11 . Even I have tested the three
simulator and all are giving 2'b11 as output
with One of them is showing warning as port size differ in port
connection.
-dhiRAj
Bresticker, Shalom wrote:
Consider the
following code:
module
bot(input [1:0] i);
initial #10
$displayb(i);
We have a
port connection of '1 to a 2-bit port.
I would
expect '1 to expand to 2'b11 without a problem.
In fact, the
three simulators I tested showed different behaviors.
One did in
fact show that i was assigned 2'b11 without any problem.
One
simulator also assigned 2'b11 to i, but also issued a port-size
mismatch
warning.
One simulator
also issued such a warning and assigned 2'bz1 to i.
What is the
correct behavior?
Intel LAD
DA, Jerusalem, Israel
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