[FFmpeg-devel] [PATCH 1/3] riscv: add CPU flags for the RISC-V Vector extension

[Lynne]

Sep 3, 2022, 21:01 by remi at remlab.net:

> From: Rémi Denis-Courmont <remi at remlab.net>
>
> RVV defines a total of 12 different extensions: V, Zvl32b, Zvl64b,
> Zvl128b, Zvl256b, Zvl512b, Zvl1024b, Zve32x, Zve32f, Zve64x, Zve64f and
> Zve64d.
>
> At this stage, we don't care about the vector length extensions Zvl*,
> as most or all optimisations will be running in a loop that is
> independent on the data set size.
>

I need to know the maximum length to write an FFT.
Could you add flags for it? I don't mind a 5-bit bitfield for a log2 of it,
or one flag per length (up to 65536).