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From: Richard Henderson <rth@twiddle.net>
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Date: Fri, 26 May 2017 07:02:47 -0700
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Subject: Re: [Qemu-devel] [PATCH 06/26] target/s390x: implement LOAD PAIR
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To: Aurelien Jarno <aurelien@aurel32.net>, qemu-devel@nongnu.org
Cc: Alexander Graf <agraf@suse.de>

On 05/25/2017 02:04 PM, Aurelien Jarno wrote:
> +static ExitStatus op_lpq(DisasContext *s, DisasOps *o)
> +{
> +    /* In a parallel context, stop the world and single step.  */
> +    if (parallel_cpus) {
> +        potential_page_fault(s);
> +        gen_exception(EXCP_ATOMIC);
> +        return EXIT_NORETURN;
> +    }
> +
> +    /* In a serial context, perform the two loads ... */
> +    tcg_gen_qemu_ld64(o->out, o->in2, get_mem_index(s));
> +    tcg_gen_addi_i64(o->in2, o->in2, 8);
> +    tcg_gen_qemu_ld64(o->out2, o->in2, get_mem_index(s));
> +    return NO_EXIT;
> +}

This can be implemented in a parallel context with helper_atomic_ldo_be_mmu, 
though that must be done with a helper function.


r~