On 12/08/2015 04:08 AM, Liang Li wrote:
> +++ b/util/buffer-zero-avx2.c
> @@ -0,0 +1,54 @@
> +#include "qemu-common.h"
> +
> +#if defined CONFIG_IFUNC && defined CONFIG_AVX2
> +#include <immintrin.h>
> +#define AVX2_VECTYPE __m256i
> +#define AVX2_SPLAT(p) _mm256_set1_epi8(*(p))
> +#define AVX2_ALL_EQ(v1, v2) \
> + (_mm256_movemask_epi8(_mm256_cmpeq_epi8(v1, v2)) == 0xFFFFFFFF)
> +#define AVX2_VEC_OR(v1, v2) (_mm256_or_si256(v1, v2))
> +
> +inline bool
> +can_use_buffer_find_nonzero_offset_avx2(const void *buf, size_t len)
> +{
> + return (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
> + * sizeof(AVX2_VECTYPE)) == 0
> + && ((uintptr_t) buf) % sizeof(AVX2_VECTYPE) == 0);
> +}
I'm not keen on adding a new file for this. You ought to be able to use
__attribute__((target("-mavx2"))) on any compiler that supports the
command-line option. Which means you can do this all in one file with static
functions.
Nor am I keen on marking a function inline when we know it must be out-of-line
because of the ifunc usage.
r~
