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Re: [Qemu-devel] [PATCH] softfloat: Don't execute divdeu without power7
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH] softfloat: Don't execute divdeu without power7 |
Date: |
Thu, 1 Nov 2018 23:49:01 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
On 01/11/2018 21:26, Richard Henderson wrote:
> The divdeu instruction was added to ISA 2.06 (Power7).
> Exclude this block from older cpus.
>
> Fixes: 27ae5109a2ba (softfloat: Specialize udiv_qrnnd for ppc64)
> Reported-by: Laurent Vivier <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> include/fpu/softfloat-macros.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/fpu/softfloat-macros.h b/include/fpu/softfloat-macros.h
> index c86687fa5e..b1d772e6d4 100644
> --- a/include/fpu/softfloat-macros.h
> +++ b/include/fpu/softfloat-macros.h
> @@ -647,8 +647,8 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t
> n1,
> asm("dlgr %0, %1" : "+r"(n) : "r"(d));
> *r = n >> 64;
> return n;
> -#elif defined(_ARCH_PPC64)
> - /* From Power ISA 3.0B, programming note for divdeu. */
> +#elif defined(_ARCH_PPC64) && defined(_ARCH_PWR7)
> + /* From Power ISA 2.06, programming note for divdeu. */
> uint64_t q1, q2, Q, r1, r2, R;
> asm("divdeu %0,%2,%4; divdu %1,%3,%4"
> : "=&r"(q1), "=r"(q2)
>
Tested-by: Laurent Vivier <address@hidden>
Reviewed-by: Laurent Vivier <address@hidden>