Martin wrote:
On Mon, Sep 22, 2008 at 09:46:07PM +0200, Vincent wrote:Since eons I've had "-msse2 -mfpmath=sse -march=pentium4" in my /etc/mk.conf, resulting in my i386 kernel being built with thoseReally? Are you sure the makeoptions CPUFLAGS from within the kernel are not overriding these? I'm not (as I don't know all the precedence off the top of my head). You could try a kernel with the above makeoptions and see if you could crash that ...
No, I clearly see the flags as the kernel files are compiled.AFAIK, I believed GCC was using SSE for the sole purpose of performing FP operations.
You are right in saying this is no guaranteed behavior, yet, if I read the GCC doc correctly, the x86 flavor of GCC turns on these flags automatically. If this is correct, and SSE operations were to be used for integer arithmetic, no amd64 kernel would work...
Vincent