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From: David Hildenbrand <david@redhat.com>
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Date: Thu, 28 Feb 2019 10:11:57 +0100
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Subject: Re: [Qemu-devel] [PATCH v1 29/33] s390x/tcg: Implement VECTOR STORE
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To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Cc: qemu-s390x@nongnu.org, Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>, Richard Henderson <rth@twiddle.net>

On 28.02.19 00:46, Richard Henderson wrote:
> On 2/26/19 3:39 AM, David Hildenbrand wrote:
>> +static DisasJumpType op_vst(DisasContext *s, DisasOps *o)
>> +{
>> +    /*
>> +     * FIXME: On exceptions we must not modify any memory.
>> +     */
>> +    store_vec_element(s, get_field(s->fields, v1), 0, o->addr1, MO_64);
>> +    gen_addi_and_wrap_i64(s, o->addr1, o->addr1, 8);
>> +    store_vec_element(s, get_field(s->fields, v1), 1, o->addr1, MO_64);
>> +    return DISAS_NEXT;
> 
> Should handle alignment though.

Again, as unaligned access must not trigger an exception, I don't think
we can use MO_ALIGN.

> 
> FWIW, there is a probe_write function that can be called to make sure a region
> is writable before actually accessing it.  But this is common enough that we
> should probably just handle 16-byte quantities as a native tcg type.

That would make most sense. It won't help for the VECTOR_STORE_MULTIPLE
part, though.

I'll keep it as is for now.

Thanks!

> 
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> 
> 
> r~
> 


-- 

Thanks,

David / dhildenb