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

Rémi Denis-Courmont remi at remlab.net
Tue Apr 30 15:49:56 EEST 2024



Le 30 avril 2024 11:22:31 GMT+03:00, flow gg <hlefthleft at gmail.com> a écrit :
>Since the number of stores is controlled by a3 and not by zero, it doesn't
>have to be exactly 16 bytes ?

Yeah ok, I get it now 
>
>Rémi Denis-Courmont <remi at remlab.net> 于2024年4月30日周二 14:40写道:
>
>>
>>
>> Le 30 avril 2024 03:26:25 GMT+03:00, flow gg <hlefthleft at 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 at 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
>> >> http://www.remlab.net/
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