[Mono-list] Problems with arrays over 4gb on 64 bit Itanium

Christian Prokopp prokopp at gmail.com
Wed Dec 10 09:10:01 EST 2008


Dear John,

A very good thought. I tried and compiled my version with
--enable-big-arrays and had no success. In fact my array index size seems to
be limited to (2^31)-1. If I try to create an array of bool or byte of 2^32
or bigger I get a System.OverflowException. If I try and create an array of
that size with double I get an OutOfMemoryException instead of the overflow.

It appears that big arrays are still not fully working (
http://go-mono.com/forums/#nabble-td19839697). Anyone has an idea when they
will work and if that solves my original out of memory problem?

Cheers,
Christian



2008/12/10 Dallman, John <john.dallman at siemens.com>

> > Thanks for the idea Alan but the big array switch is for array index
> > size over 32bit. In my case the index is smaller (factor 8 because I
> > use double) but the memory the array data covers exceeds 4gb and that
> > raises the problem.
>
> Try it anyway. On a byte-addressed machine like Itanium, using an
> integer as an index for an array of doubles will result in the
> integer being multiplied by eight before it's added to the base
> address of the array. So the addressing will actually be in terms
> of bytes. And the big array switch could well be documented in
> terms of the memory being addressed, which is what really matters.
>
> --
> John Dallman
> Parasolid Porting Engineer
>
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