[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-arm] [Qemu-devel] [PATCH v3 1/1] target-arm: Use Neon for zero
From: |
Peter Maydell |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH v3 1/1] target-arm: Use Neon for zero checking |
Date: |
Mon, 11 Jul 2016 18:55:44 +0100 |
On 5 July 2016 at 13:24, Vijay Kilari <address@hidden> wrote:
> On Sat, Jul 2, 2016 at 3:37 AM, Richard Henderson <address@hidden> wrote:
>> Consider
>>
>> #define VECTYPE uint32x4_t
>> #define ALL_EQ(v1, v2) (vmaxvq_u32((v1) ^ (v2)) == 0)
>>
>>
>> which compiles down to
>>
>> 1c: 6e211c00 eor v0.16b, v0.16b, v1.16b
>> 20: 6eb0a800 umaxv s0, v0.4s
>> 24: 1e260000 fmov w0, s0
>> 28: 6b1f001f cmp w0, wzr
>> 2c: 1a9f17e0 cset w0, eq
>> 30: d65f03c0 ret
>
> For me this code compiles as below and migration time is ~100ms more.
Thanks for benchmarking this. I'll take your original patch into
target-arm.next.
-- PMM