Re: Skill-C interface

It does depend heavily on how you write the code though - there are good ways
and bad ways of dealing with lists of data to avoid excessive creation and
destruction of list cells (i.e. you don't want to spend all your time in garbage
collection).

That said, we are looking at ways of avoiding the list creation in the first
place (but this is just an idea for a future release - we need to see if there
is really a performance benefit).

Comparing with perl is not entirely fair, because providing a SKILL-C interface
would not be that hard - but almost certainly that would not be enough. People
would want to be able to define their own object types (and this has to be done
at initialisation time, I think), and be able to access all the other data types
already existing in SKILL, and access the graphics, and access the UI, and
access the database, etc. That's what would make it costly to do. Not the
relatively simple SKILL-C interface.

Regards,

Andrew.

On Tue, 25 Nov 2003 17:02:03 -0700, sampath <[EMAIL PROTECTED]> wrote:

>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
>

--
Andrew Beckett
Senior Technical Leader
Custom IC Solutions
Cadence Design Systems Ltd