Re: poke4 won't accept my 32bit values
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Chris:
I finally got around to trying your program.
Since you aren't using Win32Lib,
I tried your program using safe.e in place
of the regular machine.e.
I did the following:
copy \euphoria\include\safe.e .
rename safe.e machine.e
Then I ran Derek's "working demo.exw".
After a few seconds safe.e reported a call
to poke() that is poking out of bounds, and it gave
me an ex.err dump (attached).
Here's what's happening.
In poke_words() in exotica_api.ew
you have a loop that is poking values.
On the final iteration of the loop you (or Todd?) are
stepping out of bounds. Although you are
storing 2-byte values, you are actually poking
4-bytes at a time (from int_to_bytes()), while
advancing the address only by 2.
This is strange, but it works, except
that on the final iteration you write 2 bytes
out of bounds. pwCubeIndices is allocated a block
that's 2-bytes too small. I gave it a couple of extra
bytes and the safe.e report went away. However,
I think I have an old version of directx, so my system
hangs beyond that point.
What does this have to do with poke4 and FFFFFFFF?
Well, the interpreter can't store FFFFFFFF as a
Euphoria 31-bit integer, so it allocates a place in the heap
memory for a double. It's just possible that you are
overwriting this double, thereby changing the value
of this literal "constant" in the program.
Any change to the program, such as shuffling statements
around, do things in a slightly different way, could possibly
change what is stored just after your block of memory,
and could make the program either work or not.
This naturally leads to all sorts of wild theories as
to what might be happening.
Anyway, fix this bug and carry on.
There may be other bugs. I can't tell.
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
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