Re: SDL crashing
On Sunday 06 April 2003 01:10 am, you wrote:
> Done and done... well it doesnt crash anymore. I dont know C
> nevermind gcc options, but i'm guess -mieee causes a float to
> go to 0 when an error occurs cause now some weird stuff
> happens in the game that i'm trying to play. Like objects
> suddenly moving to the top left of the screen. I guess
> beggars cant be choosers.
Many Alphas don't quite conform to IEEE754 floating-point specs
wrt handling NaN and plus/minus infinity, at least not without
help from the software ("software floating-point completion").
With some floating-point apps, this causes unexpected behavior
at run-time (like SIGFPE). -mieee causes gcc to generate code
where software FP completion can work.
-mieee _should_ make the software behave just as it would on x86
or any IEEE754-compliant FPU. It's not all that's required,
though; the kernel has to properly trap floating-point
exceptions and do the completion itself for this to fully work.
-mieee just sets up the assembly code so that the kernel can do
its part reliably.
(BTW, -mieee may cause a bit of a performance hit. How much
depends on your Alpha processor and the app itself, but
generally I've seen it cause about a 5-10% hit on my EV56.
AFAIK -mieee causes no performance hit on EV6 and later, but I
have no such system.)
--
Kelledin
"If a server crashes in a server farm and no one pings it, does
it still cost four figures to fix?"
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