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FFmpeg/libavcodec/riscv/opusdsp_rvv.S
Rémi Denis-Courmont bfc69297c5 lavc/opusdsp: RISC-V V (512-bit) postfilter
This adds a variant of the postfilter for use with 512-bit vectors.
Half a vector is enough to perform the scalar product. Normally a whole
vector would be used anyhow. Indeed fractional multiplers are no faster
than the unit multipler.

But in this particular function, a full vector makes up 16 samples,
which would be loaded at each iteration of the outer loop. The minimum
guaranteed CELT postfilter period is only 15. Accounting for the edges,
we can only safely preload up to 13 samples.

The fractional multipler is thus used to cap the selected vector length
to a safe value of 8 elements or 256 bits.

Likewise, we have the 1024-bit variant with the quarter multipler. In
theory, a 2048-bit one would be possible with the eigth multipler, but
that length is not even defined in the specifications as of yet, nor is
it supported by any emulator - forget actual hardware.
2022-10-10 02:23:17 +02:00

76 lines
2.2 KiB
ArmAsm

/*
* Copyright © 2022 Rémi Denis-Courmont.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/riscv/asm.S"
func ff_opus_postfilter_rvv_128, zve32f
lvtypei a5, e32, m2, ta, ma
j 1f
endfunc
func ff_opus_postfilter_rvv_512, zve32f
lvtypei a5, e32, mf2, ta, ma
j 1f
endfunc
func ff_opus_postfilter_rvv_1024, zve32f
lvtypei a5, e32, mf4, ta, ma
j 1f
endfunc
func ff_opus_postfilter_rvv_256, zve32f
lvtypei a5, e32, m1, ta, ma
1:
li a4, 5
addi a1, a1, 2
slli a1, a1, 2
lw t1, 4(a2)
vsetivli zero, 3, e32, m1, ta, ma
vle32.v v24, (a2)
sub a1, a0, a1 // a1 = &x4 = &data[-(period + 2)]
vsetvl zero, a4, a5
vslide1up.vx v8, v24, t1
lw t2, 8(a2)
vle32.v v16, (a1)
vslide1up.vx v24, v8, t2 // v24 = { g[2], g[1], g[0], g[1], g[2] }
2:
vsetvl t0, a3, a5
vle32.v v0, (a0)
sub a3, a3, t0
3:
vsetvl zero, a4, a5
lw t2, 20(a1)
vfmul.vv v8, v24, v16
addi a0, a0, 4
vslide1down.vx v16, v16, t2
addi a1, a1, 4
vfredusum.vs v0, v8, v0
vsetvl zero, t0, a5
vmv.x.s t1, v0
addi t0, t0, -1
vslide1down.vx v0, v0, zero
sw t1, -4(a0)
bnez t0, 3b
bnez a3, 2b
ret
endfunc