Re: [FFmpeg-devel] [PATCH 2/2] lavc/blockdsp: R-V V fill_block

["Rémi Denis-Courmont" <remi@remlab.net>]

Le 30 avril 2024 03:26:25 GMT+03:00, flow gg <hlefthleft@gmail.com> a écrit :
>Hi, I initially used a loop, but according to libavcodec/blockdsp.h,
>
>the maximum is 8x16 = 128 bytes, so using ff_get_rv_vlenb() >= 16 and m8
>does not require a loop.

It's okay to assume that VLENB is at least 16 bytes (as long as it's checked), but the code seems to assume (?) that it's *exactly* 16 bytes, which will break on future hardware.

>
>```
>/* add and put pixel (decoding)
> * Block sizes for op_pixels_func are 8x4,8x8 16x8 16x16.
> * h for op_pixels_func is limited to { width / 2, width },
> * but never larger than 16 and never smaller than 4. */
>typedef void (*op_fill_func)(uint8_t *block /* align width (8 or 16) */,
>                             uint8_t value, ptrdiff_t line_size, int h);
>```
>
>Rémi Denis-Courmont <remi@remlab.net> 于2024年4月30日周二 01:31写道：
>
>> Le maanantaina 29. huhtikuuta 2024, 10.09.41 EEST flow gg a écrit :
>> >
>>
>> Are you sure that this works with all vector lengths?
>> The block8 code looks odd.
>>
>> --
>> レミ・デニ-クールモン
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