Re: [ros-dev] CRT source code issue - Ros-dev

6 Aug 2007

Yes, the whole issue is at pushing operands to stack, performing well- 
documented assembly instructions to perform the asked action (div,  
mul, shl, shr, etc), and handling some special, though obvious, cases  
(like if you do a shl of some longlong number by more than 64 bits,  
you always end up with 0, there is no need to call math instructions  
in order to compute this).

I will let you know results when I speak with SDL.

WBR,
Aleksey Bragin.

On Aug 4, 2007, at 8:52 PM, Daniel Hazelton wrote:

...
  On Saturday 04 August 2007 12:28:09 Aleksey Bragin
wrote:

 I can't see where that file has anything to do with the functions  
 (e.g:
 sqrt()/alldiv()) that Betov claims are duplicated. (I've gone  
 through that
 file and can't find any single place where it does any more math than
 controlled bit-shifts. No advanced math or anything.)

 While there might be similar code, for, say, memory barriers, that  
 codes
 construction would be dictated by the specification of the target  
 machine
 (and, to some extent, the OS). If the code for sqrt/alldiv is the same
 between SDL/ROS I don't see a problem - they are both GNU projects  
 and "cross
 pollination" like that is legal.

 Whats more is that, while assembly is abstract enough to let some  
 things be
 done in more than one way, most of the more complex functionality -  
 like math
 algorithms - are so limited in the possibilities of variation that  
 I can
 easily see two unconnected people arriving at the exact same  
 solution. QED:
 Even if the code appears identical (except for things like variable  
 names,
 et. al) there is a compelling reason for it and it does not mean  
 the code has
 been copied in any way, shape or form. (And if you look at the ROS  
 commit
 history I'm sure the code in question existed before MS released  
 the SSCLI2.0
 source. Which means that the code can't be an "illegal use of MS  
 property" -
 it was around before said property was available).

 ...Okay, enough of this outsider sticking his neck out. I've said  
 enough and
 it's time to disappear and wait for a really usable version of ROS  
 to hit.
 (though I have compared it to XP under Qemu and ROS rocks!)

 DRH 