Date: Wed, 5 May 2004 21:31:38 -0700 From: David Schultz <das@FreeBSD.ORG> To: Marcel Moolenaar <marcel@xcllnt.net> Cc: alpha@FreeBSD.ORG Subject: Re: Problems with floating point exception flags Message-ID: <20040506043137.GA10641@VARK.homeunix.com> In-Reply-To: <20040506020629.GA23555@dhcp01.pn.xcllnt.net> References: <20040428064116.GA7870@VARK.homeunix.com> <20040504133904.GA22084@VARK.homeunix.com> <20040506020629.GA23555@dhcp01.pn.xcllnt.net>
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On Wed, May 05, 2004, Marcel Moolenaar wrote: > On Tue, May 04, 2004 at 06:39:04AM -0700, David Schultz wrote: > > > > Here is a better kernel patch. Instead of treating all the bits > > of the FPCR as sticky, it merely treats the exception flags that > > way. After reading the source carefully, I'm pretty sure this is > > the right fix, but I can't test it without working hardware. > > I also uncovered a bug in the way the software floating-point > > routines handle underflow. See below. > > I built and booted a kernel with these patches. Trying to exercise the > code with the files at http://people.freebsd.org/~das/alpha yield: Thanks! > alpha% ./te > Should be 00: 00 > Floating exception (core dumped) > May 5 19:00:11 alpha kernel: pid 638 (te), uid 4152: exited on signal 8 (core dumped) You need to compile the program with gcc's -mieee option in order to get floating point to work in a reasonable way on alpha. If you could try the program compiled with -mieee, that would be great.
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