Orchid XP v8 wrote:
> Surely if you wanted to build an entire game completely from scratch, 
> building the game engine would be a *relatively* small part of the 
> problem - but it's not trivial by any stretch of the imagination. 

Certainly. I'm just wondering about the relative percentages. I think enough 
people rebuild engines from scratch when they need to that it obviously 
isn't ridiculously undoable.

>>
>> It doesn't have to be identical functionality. It only has to be 
>> "correct."
> 
> No - has has to be "incorrect" in exactly the same way that Windows 
> implements it incorrectly.

It only has to be incorrect in the way that's consistent for all the 
programs you want to support. If a virus takes advantage of a buffer 
overflow, but no legitimate program does, you don't have to have the buffer 
overflow work the same way.

More likely, if Win98 allocates memory on 2-byte boundaries, and WinNT et al 
allocates it on four-byte boundaries, and you're happy not supporting Win98 
binaries on your WINE, you don't need the code to allocate on 2-byte 
boundaries. Anyone who depends on which boundary you allocate on will either 
work, or fail in a way that you know isn't supported.

 > Every bug and glitch has to be precisely
> replicated, or some lump of software somewhere that depends on those 
> bugs won't work right.

Only the bugs and glitches that some piece of software you want to support 
depends on needs to be implemented. And when you find that software failing, 
you now have a test case to figure out what real Windows is doing that your 
code isn't.

-- 
   Darren New, San Diego CA, USA (PST)
   The NFL should go international. I'd pay to
   see the Detroit Lions vs the Roman Catholics.

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