mirror of https://github.com/xemu-project/xemu.git
0f1944735b
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 <julian@codesourcery.com> Message-id: 1481130858-31767-1-git-send-email-julian@codesourcery.com Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> |
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