On 7 December 2016 at 17:14, Julian Brown <[email protected]> wrote: > The value of the MVFR1 (Media and VFP Feature Register 1) register for > the Cortex-A8 appears to be incorrect (according to the TRM, DDI0344K), > with the "full denormal arithmetic" and "propagation of NaN" fields > holding both 0 instead of both 1. > > I had a go tracing the history of the use of this value, and it seems > it's always just been wrong in QEMU: maybe it was derived from early > documentation, or guessed based on the use of a "VFP Lite" implementation > in the Cortex-A8. > > Depending on the startup/early-boot code in use, this can manifest as > failure to perform denormal arithmetic properly: in our case, selecting > a Cortex-A8 CPU when using QEMU as an instruction-set simulator for > bare-metal GCC testing caused tests using denormal arithmetic to > fail. Problems might be masked (or not occur) when using a full OS kernel > with suitable trap handlers (I'm not sure). > > Signed-off-by: Julian Brown <[email protected]>
Applied to target-arm.next for 2.9, thanks. -- PMM
