OpenEuphoria

Re: Where is my DLL?

• Posted by Robert Craig <rds at RapidEuphoria.com> Oct 19, 2005
• 543 views

Matt Lewis wrote:
> 
> Juergen Luethje wrote:
> > 
> > Sorry, I don't want to bother anyone.
> 
> It's no bother.  If we didn't want to be bothered, we wouldn't read this
> list. :)
> 
> > 
> > Now I tested the following, which *seems* to work. I use this include
> > file in my Eu program:
> > 
> > --------------------------[ dll_instance.e ]--------------------------
> > }}}
<eucode>
> > integer DLL_Instance_Hi, DLL_Instance_Lo
> > -- DLL_Instance_Hi = 0           -- Initialize the variables only when
> > -- DLL_Instance_Lo = 0           -- testing the program with the
> >                                  -- interpreter, *not* when compiling
> >                                  -- to a DLL!
> > global function dll_instance()
> >    return DLL_Instance_Hi*#10000 + DLL_Instance_Lo
> > end function
> > </eucode>
{{{

> > ----------------------------------------------------------------------
> > 
> > 
> > After translating the program for Borland, in "main_.c" I added two
> > lines to DllMain(), so that it looks like this:
> > 
> > int __declspec (dllexport) __stdcall DllMain(int hDLL, int Reason, void
> > *Reserved)
> > {
> >     _9DLL_Instance_Hi = (hDLL >> 16) & 0xFFFF;    // line added manually
> >     _9DLL_Instance_Lo = hDLL & 0xFFFF;            // line added manually
> >     if (Reason == 1)
> >         EuInit();
> >     return 1;
> > }
> > 
> > Could one of our experts please tell me whether this can be considered
> > safe?

Juergen, your multiplication code looks correct.

> That should work, since you're guaranteed to have a valid 31-bit integer.
> You could alternatively do this (which is what make_atom does):
> 
> if( (unsigned)hDLL > (unsigned)0x7fffffff)
>   {  _9DLL_Instance = NewDouble( (double)(unsigned long) hDLL ); Ref(hDLL);}

Matt, the Ref(hDLL) should be deleted. 
Ref should not be applied to a general 32-bit integer,
just to a 32-bit Euphoria object (a 31-bit integer, or a pointer), 
and it isn't needed anyway because NewDouble will set 
the ref-count to 1, which should be fine.
(Ref will be a no-op on a 31-bit Euphoria integer, so it won't do
any damage in that very common case.)

Also, you should change 0x7fffffff to 0x3fffffff, though 
your way will work by luck in many cases.

Maybe you should check make_atom as well.
(This bit fiddling stuff is very tricky. I hope I'm right here!)

For those who like bit fiddling, here is a 
chart of Euphoria internal 32-bit codes taken
from execute.h in the source:

  unused  : 011xxxxx xxxxxxxx xxxxxxxx xxxxxxxx
  unused  : 010xxxxx xxxxxxxx xxxxxxxx xxxxxxxx

  TOO_BIG:  01000000 00000000 00000000 00000000   (just too big for INT)

 +ATOM-INT: 001vvvvv vvvvvvvv vvvvvvvv vvvvvvvv   (31-bit integer value)
 +ATOM-INT: 000vvvvv vvvvvvvv vvvvvvvv vvvvvvvv   (31-bit integer value)
 -ATOM-INT: 111vvvvv vvvvvvvv vvvvvvvv vvvvvvvv   (31-bit integer value)
 -ATOM-INT: 110vvvvv vvvvvvvv vvvvvvvv vvvvvvvv   (31-bit integer value)

  NO VALUE: 10111111 11111111 11111111 11111111   (undefined object)

  ATOM-DBL: 101ppppp pppppppp pppppppp pppppppp   (29-bit pointer)

  SEQUENCE: 100ppppp pppppppp pppppppp pppppppp   (29-bit pointer)

8-byte alignment is always ensured when allocating 
sequence and double blocks, so the lower 3 bits of the address
are redundant, i.e only 29 bits are stored.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com