Re: [Linux-ia64] avoiding float underflow software assist

From: David Mosberger <davidm_at_hpl.hp.com>
Date: 2000-10-10 03:02:53
>>>>> On Mon, 9 Oct 2000 17:37:35 +0200 (MET DST), Dan Pop <Dan.Pop@cern.ch> said:

  Dan> #include <asm/fpu.h>

Please don't do this.  Applications must not include Linux kernel
header files.

The correct way of doing this is to do:

	#include <fenv.h>

	fesetenv (FE_NONIEEE_ENV);

or to compile with -ffast-math.  For the former to work, you need
glibc-2.2.  For the latter, you need both glibc-2.2 and some mods to
the compiler (which probably don't exist yet).

If you want to avoid the those complications, you can turn off
flush-to-zero mode with the following hack:

        asm volatile ("mov ar.fpsr=%0" :: "r"(0x9804c0270037f));

It's only a hack, but it should do for now.

	--david
Received on Mon Oct 09 09:02:57 2000

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