Re: [sample] A sample program for MRS emulation

[Suzuki K Poulose]

On 30/11/16 16:27, Dave Martin wrote:

On Wed, Nov 30, 2016 at 03:15:01PM +0000, Suzuki K Poulose wrote:

Here is a sample program which demonstrates how to use mrs
emulation to fetch the ID registers.

Are we planning to add this in Documentation/?  If so, we might want
some tweaks (noted below).

Dave,

Thanks for taking a look. Apologies for the late response. We could
either add it to the Documentation or stick it into samples/. I prefer
the Documentation, as it would help the text.

----8>----
/*
 * Sample program to demonstrate the MRS emulation
 * ABI.

overwrapped?

will fix it.

int main()

(void)

{

We don't wan't people using the MRS emulation without checking for its
availability first.

Something like this may work (untested), with the caveat that getauxval()
is a GNU libc extension, and other environments may require a different
mechanism to obtain the hwcaps.

Makes sense.

--8<--

#include <sys/auxv.h>
#include <asm/hwcap.h>

/* ... */

        if (!getauxval(AT_HWCAP) & HWCAP_CPUID) {
                fputs("CPUID registers unavailable\n", stderr);
                return 1;
        }

-->8--

Cheers
Suzuki