Message-ID: <3AA60D9F.FEABC67A@dspace.de> Date: Wed, 07 Mar 2001 11:29:51 +0100 From: Andreas Schreckenberg Reply-To: Andreas Schreckenberg MIME-Version: 1.0 To: linuxppc-embedded@lists.linuxppc.org Subject: how to use fp unit in kernel Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: hello, i got a floating point unavialable exception, if i use floating point instructions within a module in the kernel. why ? (kernel 2.4.0 on a PPC750 board) the kernel is compiled with -msoft-float, and my kernel module whithout this option. If i compile the kernel without -msoft-float, i cannot insert my module because some __xxxx symbols cannot be resolved by the module linker. (i linked my module static again the math library libm.a, so sin(x) should be available) the kernel receives a trap 0x800 (fp unavailable) prints a message: floating point used in kernel (task=%p, pc=%x)\n turns on the fp in the msr and exit. what must i do ? best thing whould be: everything in kernelmode should use the fp unit ? is that the best or not (performance) ? What do the enable_kernel_fp() function ? at which moment must this be invoked. i would thank you for any help Andreas -- Life's not fair. But the root password helps ! :-) http://schrecky.home.pages.de Open minds. Open sources. Open future. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/