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FFmpeg/libavcodec/x86/takdsp.asm
Lynne bbe95f7353
x86: replace explicit REP_RETs with RETs
From x86inc:
> On AMD cpus <=K10, an ordinary ret is slow if it immediately follows either
> a branch or a branch target. So switch to a 2-byte form of ret in that case.
> We can automatically detect "follows a branch", but not a branch target.
> (SSSE3 is a sufficient condition to know that your cpu doesn't have this problem.)

x86inc can automatically determine whether to use REP_RET rather than
REP in most of these cases, so impact is minimal. Additionally, a few
REP_RETs were used unnecessary, despite the return being nowhere near a
branch.

The only CPUs affected were AMD K10s, made between 2007 and 2011, 16
years ago and 12 years ago, respectively.

In the future, everyone involved with x86inc should consider dropping
REP_RETs altogether.
2023-02-01 04:23:55 +01:00

117 lines
4.0 KiB
NASM

;******************************************************************************
;* TAK DSP SIMD optimizations
;*
;* Copyright (C) 2015 Paul B Mahol
;*
;* 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/x86/x86util.asm"
SECTION_RODATA
pd_128: times 4 dd 128
SECTION .text
INIT_XMM sse2
cglobal tak_decorrelate_ls, 3, 3, 2, p1, p2, length
shl lengthd, 2
add p1q, lengthq
add p2q, lengthq
neg lengthq
.loop:
mova m0, [p1q+lengthq+mmsize*0]
mova m1, [p1q+lengthq+mmsize*1]
paddd m0, [p2q+lengthq+mmsize*0]
paddd m1, [p2q+lengthq+mmsize*1]
mova [p2q+lengthq+mmsize*0], m0
mova [p2q+lengthq+mmsize*1], m1
add lengthq, mmsize*2
jl .loop
RET
cglobal tak_decorrelate_sr, 3, 3, 2, p1, p2, length
shl lengthd, 2
add p1q, lengthq
add p2q, lengthq
neg lengthq
.loop:
mova m0, [p2q+lengthq+mmsize*0]
mova m1, [p2q+lengthq+mmsize*1]
psubd m0, [p1q+lengthq+mmsize*0]
psubd m1, [p1q+lengthq+mmsize*1]
mova [p1q+lengthq+mmsize*0], m0
mova [p1q+lengthq+mmsize*1], m1
add lengthq, mmsize*2
jl .loop
RET
cglobal tak_decorrelate_sm, 3, 3, 6, p1, p2, length
shl lengthd, 2
add p1q, lengthq
add p2q, lengthq
neg lengthq
.loop:
mova m0, [p1q+lengthq]
mova m1, [p2q+lengthq]
mova m3, [p1q+lengthq+mmsize]
mova m4, [p2q+lengthq+mmsize]
mova m2, m1
mova m5, m4
psrad m2, 1
psrad m5, 1
psubd m0, m2
psubd m3, m5
paddd m1, m0
paddd m4, m3
mova [p1q+lengthq], m0
mova [p2q+lengthq], m1
mova [p1q+lengthq+mmsize], m3
mova [p2q+lengthq+mmsize], m4
add lengthq, mmsize*2
jl .loop
RET
INIT_XMM sse4
cglobal tak_decorrelate_sf, 3, 3, 5, p1, p2, length, dshift, dfactor
shl lengthd, 2
add p1q, lengthq
add p2q, lengthq
neg lengthq
movd m2, dshiftm
movd m3, dfactorm
pshufd m3, m3, 0
mova m4, [pd_128]
.loop:
mova m0, [p1q+lengthq]
mova m1, [p2q+lengthq]
psrad m1, m2
pmulld m1, m3
paddd m1, m4
psrad m1, 8
pslld m1, m2
psubd m1, m0
mova [p1q+lengthq], m1
add lengthq, mmsize
jl .loop
RET