[FFmpeg-devel] [PATCH] aarch64: Factorize code for CPU feature detection on Apple platforms

[Martin Storsjö]

On Tue, 12 Mar 2024, Martin Storsjö wrote:

> ---
> libavutil/aarch64/cpu.c | 25 +++++++++++++------------
> 1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/libavutil/aarch64/cpu.c b/libavutil/aarch64/cpu.c
> index 7a05391343..196bdaf6b0 100644
> --- a/libavutil/aarch64/cpu.c
> +++ b/libavutil/aarch64/cpu.c
> @@ -45,22 +45,23 @@ static int detect_flags(void)
> #elif defined(__APPLE__) && HAVE_SYSCTLBYNAME
> #include <sys/sysctl.h>
>
> +static int have_feature(const char *feature) {
> +    uint32_t value = 0;
> +    size_t size = sizeof(value);
> +    if (!sysctlbyname(feature, &value, &size, NULL, 0))
> +        return value;
> +    return 0;
> +}
> +
> static int detect_flags(void)
> {
> -    uint32_t value = 0;
> -    size_t size;
>     int flags = 0;
>
> -    size = sizeof(value);
> -    if (!sysctlbyname("hw.optional.arm.FEAT_DotProd", &value, &size, NULL, 0)) {
> -        if (value)
> -            flags |= AV_CPU_FLAG_DOTPROD;
> -    }
> -    size = sizeof(value);
> -    if (!sysctlbyname("hw.optional.arm.FEAT_I8MM", &value, &size, NULL, 0)) {
> -        if (value)
> -            flags |= AV_CPU_FLAG_I8MM;
> -    }
> +    if (have_feature("hw.optional.arm.FEAT_DotProd"))
> +        flags |= AV_CPU_FLAG_DOTPROD;
> +    if (have_feature("hw.optional.arm.FEAT_I8MM"))
> +        flags |= AV_CPU_FLAG_I8MM;
> +
>     return flags;
> }

Will apply.

// Martin