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FFmpeg/libavcodec/x86/rv34dsp.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

170 lines
5.1 KiB
NASM

;******************************************************************************
;* MMX/SSE2-optimized functions for the RV30 and RV40 decoders
;* Copyright (C) 2012 Christophe Gisquet <christophe.gisquet@gmail.com>
;*
;* 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
pw_row_coeffs: times 4 dw 13
times 4 dw 17
times 4 dw 7
pd_512: times 2 dd 0x200
pw_col_coeffs: dw 13, 13, 13, -13
dw 17, 7, 7, -17
dw 13, -13, 13, 13
dw -7, 17, -17, -7
SECTION .text
%macro IDCT_DC_NOROUND 1
imul %1, 13*13*3
sar %1, 11
%endmacro
%macro IDCT_DC_ROUND 1
imul %1, 13*13
add %1, 0x200
sar %1, 10
%endmacro
INIT_MMX mmxext
cglobal rv34_idct_dc_noround, 1, 2, 0
movsx r1, word [r0]
IDCT_DC_NOROUND r1
movd m0, r1d
pshufw m0, m0, 0
movq [r0+ 0], m0
movq [r0+ 8], m0
movq [r0+16], m0
movq [r0+24], m0
RET
; Load coeffs and perform row transform
; Output: coeffs in mm[0467], rounder in mm5
%macro ROW_TRANSFORM 1
pxor mm7, mm7
mova mm0, [%1+ 0*8]
mova mm1, [%1+ 1*8]
mova mm2, [%1+ 2*8]
mova mm3, [%1+ 3*8]
mova [%1+ 0*8], mm7
mova [%1+ 1*8], mm7
mova [%1+ 2*8], mm7
mova [%1+ 3*8], mm7
mova mm4, mm0
mova mm6, [pw_row_coeffs+ 0]
paddsw mm0, mm2 ; b0 + b2
psubsw mm4, mm2 ; b0 - b2
pmullw mm0, mm6 ; *13 = z0
pmullw mm4, mm6 ; *13 = z1
mova mm5, mm1
pmullw mm1, [pw_row_coeffs+ 8] ; b1*17
pmullw mm5, [pw_row_coeffs+16] ; b1* 7
mova mm7, mm3
pmullw mm3, [pw_row_coeffs+ 8] ; b3*17
pmullw mm7, [pw_row_coeffs+16] ; b3* 7
paddsw mm1, mm7 ; z3 = b1*17 + b3* 7
psubsw mm5, mm3 ; z2 = b1* 7 - b3*17
mova mm7, mm0
mova mm6, mm4
paddsw mm0, mm1 ; z0 + z3
psubsw mm7, mm1 ; z0 - z3
paddsw mm4, mm5 ; z1 + z2
psubsw mm6, mm5 ; z1 - z2
mova mm5, [pd_512] ; 0x200
%endmacro
; ff_rv34_idct_add_mmxext(uint8_t *dst, ptrdiff_t stride, int16_t *block);
%macro COL_TRANSFORM 4
pshufw mm3, %2, 0xDD ; col. 1,3,1,3
pshufw %2, %2, 0x88 ; col. 0,2,0,2
pmaddwd %2, %3 ; 13*c0+13*c2 | 13*c0-13*c2 = z0 | z1
pmaddwd mm3, %4 ; 17*c1+ 7*c3 | 7*c1-17*c3 = z3 | z2
paddd %2, mm5
pshufw mm1, %2, 01001110b ; z1 | z0
pshufw mm2, mm3, 01001110b ; z2 | z3
paddd %2, mm3 ; z0+z3 | z1+z2
psubd mm1, mm2 ; z1-z2 | z0-z3
movd mm3, %1
psrad %2, 10
pxor mm2, mm2
psrad mm1, 10
punpcklbw mm3, mm2
packssdw %2, mm1
paddw %2, mm3
packuswb %2, %2
movd %1, %2
%endmacro
INIT_MMX mmxext
cglobal rv34_idct_add, 3,3,0, d, s, b
ROW_TRANSFORM bq
COL_TRANSFORM [dq], mm0, [pw_col_coeffs+ 0], [pw_col_coeffs+ 8]
mova mm0, [pw_col_coeffs+ 0]
COL_TRANSFORM [dq+sq], mm4, mm0, [pw_col_coeffs+ 8]
mova mm4, [pw_col_coeffs+ 8]
lea dq, [dq + 2*sq]
COL_TRANSFORM [dq], mm6, mm0, mm4
COL_TRANSFORM [dq+sq], mm7, mm0, mm4
ret
; ff_rv34_idct_dc_add_sse4(uint8_t *dst, int stride, int dc);
%macro RV34_IDCT_DC_ADD 0
cglobal rv34_idct_dc_add, 3, 3, 6
; load data
IDCT_DC_ROUND r2
pxor m1, m1
; calculate DC
movd m0, r2d
lea r2, [r0+r1*2]
movd m2, [r0]
movd m3, [r0+r1]
pshuflw m0, m0, 0
movd m4, [r2]
movd m5, [r2+r1]
punpcklqdq m0, m0
punpckldq m2, m3
punpckldq m4, m5
punpcklbw m2, m1
punpcklbw m4, m1
paddw m2, m0
paddw m4, m0
packuswb m2, m4
movd [r0], m2
%if cpuflag(sse4)
pextrd [r0+r1], m2, 1
pextrd [r2], m2, 2
pextrd [r2+r1], m2, 3
%else
psrldq m2, 4
movd [r0+r1], m2
psrldq m2, 4
movd [r2], m2
psrldq m2, 4
movd [r2+r1], m2
%endif
RET
%endmacro
INIT_XMM sse2
RV34_IDCT_DC_ADD
INIT_XMM sse4
RV34_IDCT_DC_ADD