On 18 February 2011 07:12, Gerhard Wiesinger <[email protected]> wrote: > Issue 1.) with FPU still present > I tracked down the problematic code and it is a rounding error from double > precision to 64bit floats: Any ideas how to fix such an issue in general? > > QEMU result in ST0: 0.42925860786976457 (wrong emulated) > KVM result in ST0: 0.42925860786975449 (correct)
This is an error when running QEMU in TCG mode, right? At the moment x86 is the odd-one-out in that it doesn't use CONFIG_SOFTFLOAT for its FPU emulation, so somebody has made an explicit choice of preferring speed over accuracy, and I am unsurprised that there are rounding errors as a result. -- PMM
