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From: "Rémi Denis-Courmont" <remi@remlab.net>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH 4/4] lavu/fixed_dsp: R-V V vector_fmul_window
Date: Thu, 05 Oct 2023 17:54:48 +0300
Message-ID: <2357615.W6rPUtsr1t@basile.remlab.net> (raw)
In-Reply-To: <20231004195110.38615-4-remi@remlab.net>

Le keskiviikkona 4. lokakuuta 2023, 22.51.10 EEST Rémi Denis-Courmont a écrit 
:
> +        vwmul.vv v12, v16, v28
> +        vwmul.vv v8, v16, v24
> +        // vwnmsac.vv does _not_ exist so multiply & subtract separately
> +        vwmul.vv v4, v20, v24
> +        vwmacc.vv v8, v20, v28

Retaining 3 whole double-width multiply vectors is really hurting here. This 
would be a lot smoother with just the top-halves (vsmul.vv), but then we need 
to round each multiplication. Of course the final results would differ slightly 
then, and I am not sure what that entails for the audio codecs (nor would I 
know how to update the x86 code).

N.B.: Don't ask for benchmarks, this can't run on v0.7.1 proto-RVV hardware.

-- 
雷米‧德尼-库尔蒙
http://www.remlab.net/



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      reply	other threads:[~2023-10-05 14:55 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-04 19:51 [FFmpeg-devel] [PATCH 1/4] lavu/fixed_dsp: R-V V vector_fmul_add Rémi Denis-Courmont
2023-10-04 19:51 ` [FFmpeg-devel] [PATCH 2/4] lavu/fixed_dsp: R-V V vector_fmul_reverse Rémi Denis-Courmont
2023-10-04 19:51 ` [FFmpeg-devel] [PATCH 3/4] lavu/fixed_dsp: R-V V vector_fmul Rémi Denis-Courmont
2023-10-04 19:51 ` [FFmpeg-devel] [PATCH 4/4] lavu/fixed_dsp: R-V V vector_fmul_window Rémi Denis-Courmont
2023-10-05 14:54   ` Rémi Denis-Courmont [this message]

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