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Re: [qemu-s390x] [PATCH v2 3/4] softfloat: Specialize udiv_qrnnd for s39


From: David Hildenbrand
Subject: Re: [qemu-s390x] [PATCH v2 3/4] softfloat: Specialize udiv_qrnnd for s390x
Date: Fri, 5 Oct 2018 11:56:12 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0

On 03/10/2018 20:07, Richard Henderson wrote:
> The ISA has a 128/64-bit division instruction.
> 
> Cc: address@hidden
> Cc: Cornelia Huck <address@hidden>
> Cc: David Hildenbrand <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  include/fpu/softfloat-macros.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/include/fpu/softfloat-macros.h b/include/fpu/softfloat-macros.h
> index 6d58615709..e702607b43 100644
> --- a/include/fpu/softfloat-macros.h
> +++ b/include/fpu/softfloat-macros.h
> @@ -626,6 +626,12 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t 
> n1,
>      uint64_t q;
>      asm("divq %4" : "=a"(q), "=d"(*r) : "0"(n0), "1"(n1), "rm"(d));
>      return q;
> +#elif defined(__s390x__)
> +    /* Need to use a TImode type to get an even register pair for DLGR.  */
> +    unsigned __int128 n = (unsigned __int128)n1 << 64 | n0;
> +    asm("dlgr %0, %1" : "+r"(n) : "r"(d));
> +    *r = n >> 64;
> +    return n;
>  #else
>      uint64_t d0, d1, q0, q1, r1, r0, m;
>  
> 

Reviewed-by: David Hildenbrand <address@hidden>

-- 

Thanks,

David / dhildenb



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