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Re: [Qemu-devel] ARM Cortex R5 + VFP3

From: Karthik
Subject: Re: [Qemu-devel] ARM Cortex R5 + VFP3
Date: Tue, 24 May 2016 19:52:14 +0530

Yeah, the micro had a secure boot ROM which we don't have access to.
Probably it is enabled there. I'll check in the target hardware.

The code generated by the compiler doesn't specifically check for
non-existent registers, so we should be good using VFP3 in place for

Best regards,
On May 24, 2016 7:31 PM, "Peter Maydell" <address@hidden> wrote:

> On 24 May 2016 at 14:49, Karthik <address@hidden> wrote:
> > ahh okay. The code I don't think writes to CPACR_EL1 register, but it
> runs
> > on the hardware anywary.
> If it does then there's probably some firmware somewhere
> which is doing the setup for you somehow.
> As you can see in the Cortex-R5 technical reference manual entry
> for CPACR:
> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0205g/Bgbjhiea.html
> the hardware reset value for bits 21..23 is 0, meaning access denied,
> and for FPEXC the EN bit is clear on reset:
> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0205g/Bgbjhiea.html
> By the way, QEMU doesn't implement VFPv3-D16, which is what the R5
> ought to have -- setting the ARM_FEATURE_VFP3 bit will give you
> 32 double-precision registers. This is probably close enough that
> guest code will work, though obviously if the guest specifically
> tests that registers 16..31 don't exist it will not behave as
> the hardware does.
> thanks
> -- PMM

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