Re: [Qemu-devel] [PATCH v4] target-sparc: Add and use CPU_FEATURE_CASA

[Sebastian Huber <sebastian.huber@embedded-brains.de>]

Hello,

exists there someone who is able to commit this?

On 2014-02-14 17:22, Andreas Färber wrote:
> Am 14.02.2014 17:06, schrieb Sebastian Huber:
>> The LEON3 processor has support for the CASA instruction which is
>> normally only available for SPARC V9 processors.  Binutils 2.24
>> and GCC 4.9 will support this instruction for LEON3.  GCC uses it to
>> generate C11 atomic operations.
>>
>> The CAS synthetic instruction uses an ASI of 0x80.  If TARGET_SPARC64 is
>> not defined use a supervisor data load/store for an ASI of 0x80 in
>> helper_ld_asi()/helper_st_asi().  The supervisor data load/store was
>> choosen according to the LEON3 documentation.
>>
>> The ASI 0x80 is defined in the SPARC V9 manual, Table 12—Address Space
>> Identifiers (ASIs).  Here we have: 0x80, ASI_PRIMARY, Unrestricted
>> access, Primary address space.
>>
>> Tested with the following program:
>>
>>    #include <assert.h>
>>    #include <stdatomic.h>
>>
>>    void test(void)
>>    {
>>      atomic_int a;
>>      int e;
>>      _Bool b;
>>
>>      atomic_store(&a, 1);
>>      e = 1;
>>      b = atomic_compare_exchange_strong(&a, &e, 2);
>>      assert(b);
>>      assert(atomic_load(&a) == 2);
>>
>>      atomic_store(&a, 3);
>>      e = 4;
>>      b = atomic_compare_exchange_strong(&a, &e, 5);
>>      assert(!b);
>>      assert(atomic_load(&a) == 3);
>>    }
>>
>> Tested also on a NGMP board with a LEON4 processor.
>>
>> v4: Fix coding style.
>>
>> Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
>> Reviewed-by: Fabien Chouteau <chouteau@adacore.com>
>
> Reviewed-by: Andreas Färber <afaerber@suse.de>
>
> but please put change logs below --- next time. No v5 needed for that,
> committer can fix.
> Also in my theory your Signed-off-by should be last when you submit a
> patch, in particular when you apply changes on top of what a reviewer
> has reviewed.
>
> Thanks,
> Andreas
>


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Sebastian Huber, embedded brains GmbH

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