Re: Skill-C interface

Hi all,
SKILL is slow especially when processing long long lists.
example I want to go through each shape in a list of some millions of 
shape to do some processing... I found that doing it in C(ITKDB) is much 
faster than SKILL. I can use ITKDB for writing stand alone 
tools/functions but  as Andrew said thats not what I want.
Mainly what I am looking for is...when I am in df2 session, already most 
of the information is in virtual memory...so as data is available 
through df2, I just need to write functions in c to operate on it, 
instead getting data again using ITKDB.
I am looking for something similar to inline C module for perl, so that 
I can access c functions in a perl module..
I dont know how tough it is to provide that type of feature for cadence 
and maintain it. Because, we can see that  TCL and PERL they all can 
handle C functions.And they work pretty well.  I have a feeling that 
many people need this type of functionality.
 BTW, Frank! you said you wrote a C++ function few yrs back and called 
it from SKILL, may I know how did u write? did you use ItkDB or IPC or 
something else?
Thanks for your responses
Sampath


Andrew Beckett wrote:
> Frank,
>
> On Tue, 25 Nov 2003 13:16:02 -0800, "gennari" <[EMAIL PROTECTED]> wrote:
>
>
> > A few years ago I had to write a separate C++ program to get around some of
> > the limitations of SKILL, and then call that program from SKILL. In
> > particular, SKILL/Cadence crashed when I tried to create a hash table of
> > several hundred thousand x/y points. Also, I couldn't find any way of
> > performing bit-level operations in SKILL such as bitshifts, bit masking,
> > etc. In fact I think skill uses 32 bits in all integers, even when I only
> > need to store an 8-bit value, and that's 4X memory overhead. I eventually
> > had to implement the layout database and gometry query functions into my C++
> > program to aviod writing I/O files of many MB. Now the program is
> > independent of Cadence, but I wonder if all that work was really worth it.
>
>
> functions such as bor, band - which are equivalent to operators | and &. Also
> bnand, bnor, bxor, bxnor (operators for each of these too).
> leftshift, rightshift (<< and >>).
> The bitfield, bitfield1 functions as well are useful. These are equivalents
> of doing something like:
>
> a=1234
> a<4:2>  => 4
> a<4> => 1
> a<<1 => 2468
> a>>2 => 308
> a&10 => 2
> a|5 => 1239
> a^2 => 1232 (xor)
>
> Bet you didn't know you could do that ;-(
>
> They're all documented, and have been there for as long as I can remember.
>
>
> > Oh, and as a side note, is there any way to create a small bitmap image in
> > Cadence other than building it from single pixel rectangles on the
> > multi-colored "y0" - "y9" layers in the LSW? It takes a really long time to
> > do this in SKILL.
>
>
> Depends what you want to use the bitmap for. If it's for menu items, icons
> etc in DFII, then hiStringToIcon and related functions would help. Some of the
> ^dl (displayList) functions can be used too (don't get used much, but can be
> quite handy).
>
> Andrew.
>
>
> > Frank
> >
> > "Andrew Beckett" <[EMAIL PROTECTED]> wrote in message
> > news:[EMAIL PROTECTED]
> >
> > > You could use the Integrators Toolkit (ITK-DB). This allows you to write
> > > standalone applications which access the database from C, and there is
> >
> > some
> >
> > > (limited) support for invoking SKILL from this.
> > >
> > > However, I suspect this is not what you want. You can't (for example) link
> >
> > in
> >
> > > some C code with DFII and call that from SKILL (we don't support that, for
> > > a variety of reasons - one being that it is rarely necessary). What you
> >
> > can do
> >
> > > however is to write your computationally intensive tasks in a separate
> >
> > program,
> >
> > > which you can then invoke using the ipc function calls (e.g.
> >
> > ipcBeginProcess),
> >
> > > and then communicate to that external program either synchronously or
> > > asynchronously. This can be quite an effective means of doing things
> >
> > outside.
> >
> > > What sort of intensive operations are you talking about? SKILL can be
> >
> > pretty
> >
> > > quick provided that you do things correctly (it's byte-code compiled,
> > > and runs on a virtual machine).
> > >
> > > Regards,
> > >
> > > Andrew.
> > >
> > >
> > > On Mon, 24 Nov 2003 15:20:13 -0700, sampath <[EMAIL PROTECTED]> wrote:
> > >
> > >
> > > > Hi,
> > > > is there anyway that i can mix skill and c code,
> > > > I am looking for a way to do some runtime intensive operations in c and
> > > > get the data into a skill code?
> > > > can somebody tell a solution?
> > > > sampath
> > >
> > > --
> > > Andrew Beckett
> > > Senior Technical Leader
> > > Custom IC Solutions
> > > Cadence Design Systems Ltd
>
> --
> Andrew Beckett
> Senior Technical Leader
> Custom IC Solutions
> Cadence Design Systems Ltd