[ibis-interconn] IBIS Sparse Matrix Label Question
- From: Bob Ross <bob@xxxxxxxxxxxxx>
- To: IBIS-Interconnect <ibis-interconn@xxxxxxxxxxxxx>
- Date: Thu, 18 Feb 2010 12:24:00 -0800
All:
At the last IBIS Interconnect meeting we had a discussion concerning
how general or how restrictive the text-based sparse-label syntax should
be, as documented on page 2, second paragraph of Draft 11:
http://www.eda.org/pub/ibis/adhoc/interconnect/index-bydate.htm
Page 4 of the Touchstone specification defines the ASCII character
set for Touchstone:
http://www.eda.org/pub/ibis/touchstone_ver2.0/touchstone_ver2_0.pdf
The issue is whether the sparse label should include white-space
(including tab) and line termination charater sequences (CR, CRLF, LF)
The original sparse-label definition paragraph in Draft 11 is:
---------------
A sparse-label is a string of one or more ASCII characters. The last character
of this string shall be the colon character ‘:’. The colon character may not
appear in the string other than as the last character. A sparse-label shall not
begin with an open parenthesis ‘(’, though this character may be present for any
character other than the first or last in the string. A sparse-label may
consist of only the colon character - a one character string “:”.
---------------
Brad Brim supplied some replacement paragraph options ranging from the
most general (white space and line termination sequences) to the
least general (no white space, line termination, and restrictive set
of characters):
----------------------------------------------------------------------
Most General
A sparse-label is a string of one or more ASCII characters, as defined in the
General Syntax Rules and Guidelines section. The last character of this string
shall be the colon character ‘:’. The colon character may not appear in the
string other than as the last character. A sparse-label shall not begin with an
open parenthesis ‘(’, though this character may be present for any character
other than the first or last in the string. A sparse-label may consist of only
the colon character - a one character string “:”.
A sparse-label is a string of one or more ASCII characters, as defined in the
General Syntax Rules and Guidelines section. The last character of this string
shall be the colon character ‘:’. The colon character may not appear in the
string other than as the last character. Whitespace (space 20h or tab 09h) or a
line termination (LF 0Ah or CR 0Dh) shall not occur in the string. A
sparse-label may consist of only the colon character - a one character string “:”.
A sparse-label is a string of one or more ASCII characters. The last character
of this string shall be the colon character ‘:’. A sparse-label may consist of
only the colon character - a one character string “:”. If the length of the
string is greater than one, then it must begin with a letter and shall contain
only letters, numbers and underscore ‘_’.
Least General
----------------------------------------------------------------------
The Touchstone 2 Specification gives the allowable ASCII characters:
1. Touchstone files are case-insensitive.
2. Only US-ASCII
a) graphic characters (i.e., code values 20h through 7Eh) ,
b) tab characters (09h), and
c)line termination sequences, e.g., LF (0Ah), CR+LF (0Dh + 0Ah), or CR (0Dh),
each encoded in 8 bits as defined in ISO/IEC 8859-1:1998 are permitted in a
Touchstone file.
----------------------------------------------------------------------
I favor the second option that keeps a label and ":" as one word without
any gaps. Otherwise, white space and/or termination sequences would
make it impossible to detect certain errors in the file such as
spurious or missing characters. For example, an extra character would
be interpreted as the beginning of the next label (including index-pair
content) and no error would be reported. The simulations might also
produce plausable, bogus results because it did not use some of
the data.
Any comments?
Bob
--
Bob Ross
Teraspeed Consulting Group LLC Teraspeed Labs
121 North River Drive 13610 SW Harness Lane
Narragansett, RI 02882 Beaverton, OR 97008
401-284-1827 503-430-1065
http://www.teraspeed.com 503-246-8048 Direct
bob@xxxxxxxxxxxxx
Teraspeed is a registered service mark of Teraspeed Consulting Group LLC
------------------------------------------------------------------
The IBIS Ad Hoc Interconnect Task Group Mailing List
Archives are available at:
//www.freelists.org/archives/ibis-interconn
TO UNSUBSCRIBE:
Send a message to "ibis-interconn-request@xxxxxxxxxxxxx"
with a subject of "unsubscribe"
To administer your subscription status from the web, visit:
//www.freelists.org/list/ibis-interconn
Other related posts:
- » [ibis-interconn] IBIS Sparse Matrix Label Question - Bob Ross
