From: David Tolpin <dvd@davidashen.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] 'fp: stack overflow'
Date: Fri, 5 Mar 2004 00:22:12 +0400 [thread overview]
Message-ID: <200403042022.i24KMCUO059009@adat.davidashen.net> (raw)
In-Reply-To: <52f9c7bb60481d1c2f85c7e455ddd165@terzarima.net>
>
> the compiler might be miscalculating the depth of the FP
> stack, allowing it to overflow at run-time.
> (alternatively, it might just be missing a pop variant in a particular case.)
> either way it would be helpful to see if you can isolate the expression(s)
> that cause the trouble.
>
The trouble is moving all around the floating point code if I am trying
to isolate it. The expressions are moderately complex, such as
Vtemp[i][j].x = (1.0 - t) * Vtemp[i-1][j].x + t * Vtemp[i-1][j+1].x
but the problem moves to another expression in another function or
another part of the library (or just to a later invocation of the same
function) if I simpify them.
I must admit that I do not remember the x86 assembler well enough
to debug. But it looks to me like FP stack is unbalanced, and
gets overflowed due to missing pops (or are they called folds?)
David
next prev parent reply other threads:[~2004-03-04 20:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-04 18:25 David Tolpin
2004-03-04 18:33 ` David Presotto
2004-03-04 18:35 ` David Tolpin
2004-03-04 18:39 ` Charles Forsyth
2004-03-04 20:22 ` David Tolpin [this message]
2004-03-04 20:30 ` David Tolpin
2004-03-04 18:40 ` David Presotto
2004-03-04 22:21 ` boyd, rounin
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