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truehd: add hand-scheduled ARM asm version of mlp_filter_channel.

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Profiling results for overall audio decode and the mlp_filter_channel(_arm)
function in particular are as follows:

              Before          After
              Mean   StdDev   Mean   StdDev  Confidence  Change
6:2 total     380.4  22.0     370.8  17.0    87.4%       +2.6%  (insignificant)
6:2 function  60.7   7.2      36.6   8.1     100.0%      +65.8%
8:2 total     357.0  17.5     343.2  19.0    97.8%       +4.0%  (insignificant)
8:2 function  60.3   8.8      37.3   3.8     100.0%      +61.8%
6:6 total     717.2  23.2     658.4  15.7    100.0%      +8.9%
6:6 function  140.4  12.9     81.5   9.2     100.0%      +72.4%
8:8 total     981.9  16.2     896.2  24.5    100.0%      +9.6%
8:8 function  193.4  15.0     103.3  11.5    100.0%      +87.2%

Experiments with adding preload instructions to this function yielded no
useful benefit, so these have not been included.

The assembly version has also been tested with a fuzz tester to ensure that
any combinations of inputs not exercised by my available test streams still
generate mathematically identical results to the C version.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
pull/64/head
Ben Avison 11 years ago committed by Michael Niedermayer
parent 3017239d3a
commit 87b128d5ef
5 changed files with 474 additions and 0 deletions
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  1. 2
      libavcodec/arm/Makefile
  2. 433
      libavcodec/arm/mlpdsp_arm.S
  3. 36
      libavcodec/arm/mlpdsp_init_arm.c
  4. 2
      libavcodec/mlpdsp.c
  5. 1
      libavcodec/mlpdsp.h

2
libavcodec/arm/Makefile
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@ -16,6 +16,8 @@ OBJS-$(CONFIG_H264PRED) += arm/h264pred_init_arm.o
OBJS-$(CONFIG_H264QPEL) += arm/h264qpel_init_arm.o OBJS-$(CONFIG_H264QPEL) += arm/h264qpel_init_arm.o
OBJS-$(CONFIG_HPELDSP) += arm/hpeldsp_init_arm.o \ OBJS-$(CONFIG_HPELDSP) += arm/hpeldsp_init_arm.o \
arm/hpeldsp_arm.o arm/hpeldsp_arm.o
OBJS-$(CONFIG_MLP_DECODER) += arm/mlpdsp_init_arm.o \
arm/mlpdsp_arm.o
OBJS-$(CONFIG_MPEGAUDIODSP) += arm/mpegaudiodsp_init_arm.o OBJS-$(CONFIG_MPEGAUDIODSP) += arm/mpegaudiodsp_init_arm.o
OBJS-$(CONFIG_MPEGVIDEO) += arm/mpegvideo_arm.o OBJS-$(CONFIG_MPEGVIDEO) += arm/mpegvideo_arm.o
OBJS-$(CONFIG_NEON_CLOBBER_TEST) += arm/neontest.o OBJS-$(CONFIG_NEON_CLOBBER_TEST) += arm/neontest.o

433
libavcodec/arm/mlpdsp_arm.S
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@ -0,0 +1,433 @@
/*
* Copyright (c) 2014 RISC OS Open Ltd
* Author: Ben Avison <bavison@riscosopen.org>
*
* 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/arm/asm.S"
#define MAX_CHANNELS 8
#define MAX_FIR_ORDER 8
#define MAX_IIR_ORDER 4
#define MAX_RATEFACTOR 4
#define MAX_BLOCKSIZE (40 * MAX_RATEFACTOR)
PST .req a1
PCO .req a2
AC0 .req a3
AC1 .req a4
CO0 .req v1
CO1 .req v2
CO2 .req v3
CO3 .req v4
ST0 .req v5
ST1 .req v6
ST2 .req sl
ST3 .req fp
I .req ip
PSAMP .req lr
// Some macros that do loads/multiplies where the register number is determined
// from an assembly-time expression. Boy is GNU assembler's syntax ugly...
.macro load group, index, base, offset
.altmacro
load_ \group, %(\index), \base, \offset
.noaltmacro
.endm
.macro load_ group, index, base, offset
ldr \group\index, [\base, #\offset]
.endm
.macro loadd group, index, base, offset
.altmacro
loadd_ \group, %(\index), %(\index+1), \base, \offset
.noaltmacro
.endm
.macro loadd_ group, index0, index1, base, offset
A .if offset >= 256
A ldr \group\index0, [\base, #\offset]
A ldr \group\index1, [\base, #(\offset) + 4]
A .else
ldrd \group\index0, \group\index1, [\base, #\offset]
A .endif
.endm
.macro multiply index, accumulate, long
.altmacro
multiply_ %(\index), \accumulate, \long
.noaltmacro
.endm
.macro multiply_ index, accumulate, long
.if \long
.if \accumulate
smlal AC0, AC1, CO\index, ST\index
.else
smull AC0, AC1, CO\index, ST\index
.endif
.else
.if \accumulate
mla AC0, CO\index, ST\index, AC0
.else
mul AC0, CO\index, ST\index
.endif
.endif
.endm
// A macro to update the load register number and load offsets
.macro inc howmany
.set LOAD_REG, (LOAD_REG + \howmany) & 3
.set OFFSET_CO, OFFSET_CO + 4 * \howmany
.set OFFSET_ST, OFFSET_ST + 4 * \howmany
.if FIR_REMAIN > 0
.set FIR_REMAIN, FIR_REMAIN - \howmany
.if FIR_REMAIN == 0
.set OFFSET_CO, 4 * MAX_FIR_ORDER
.set OFFSET_ST, 4 * (MAX_BLOCKSIZE + MAX_FIR_ORDER)
.endif
.elseif IIR_REMAIN > 0
.set IIR_REMAIN, IIR_REMAIN - \howmany
.endif
.endm
// Macro to implement the inner loop for one specific combination of parameters
.macro implement_filter mask_minus1, shift_0, shift_8, iir_taps, fir_taps
.set TOTAL_TAPS, \iir_taps + \fir_taps
// Deal with register allocation...
.set DEFINED_SHIFT, 0
.set DEFINED_MASK, 0
.set SHUFFLE_SHIFT, 0
.set SHUFFLE_MASK, 0
.set SPILL_SHIFT, 0
.set SPILL_MASK, 0
.if TOTAL_TAPS == 0
// Little register pressure in this case - just keep MASK where it was
.if !\mask_minus1
MASK .req ST1
.set DEFINED_MASK, 1
.endif
.else
.if \shift_0
.if !\mask_minus1
// AC1 is unused with shift 0
MASK .req AC1
.set DEFINED_MASK, 1
.set SHUFFLE_MASK, 1
.endif
.elseif \shift_8
.if !\mask_minus1
.if TOTAL_TAPS <= 4
// All coefficients are preloaded (so pointer not needed)
MASK .req PCO
.set DEFINED_MASK, 1
.set SHUFFLE_MASK, 1
.else
.set SPILL_MASK, 1
.endif
.endif
.else // shift not 0 or 8
.if TOTAL_TAPS <= 3
// All coefficients are preloaded, and at least one CO register is unused
.if \fir_taps & 1
SHIFT .req CO0
.set DEFINED_SHIFT, 1
.set SHUFFLE_SHIFT, 1
.else
SHIFT .req CO3
.set DEFINED_SHIFT, 1
.set SHUFFLE_SHIFT, 1
.endif
.if !\mask_minus1
MASK .req PCO
.set DEFINED_MASK, 1
.set SHUFFLE_MASK, 1
.endif
.elseif TOTAL_TAPS == 4
// All coefficients are preloaded
SHIFT .req PCO
.set DEFINED_SHIFT, 1
.set SHUFFLE_SHIFT, 1
.if !\mask_minus1
.set SPILL_MASK, 1
.endif
.else
.set SPILL_SHIFT, 1
.if !\mask_minus1
.set SPILL_MASK, 1
.endif
.endif
.endif
.endif
.if SPILL_SHIFT
SHIFT .req ST0
.set DEFINED_SHIFT, 1
.endif
.if SPILL_MASK
MASK .req ST1
.set DEFINED_MASK, 1
.endif
// Preload coefficients if possible
.if TOTAL_TAPS <= 4
.set OFFSET_CO, 0
.if \fir_taps & 1
.set LOAD_REG, 1
.else
.set LOAD_REG, 0
.endif
.rept \fir_taps
load CO, LOAD_REG, PCO, OFFSET_CO
.set LOAD_REG, (LOAD_REG + 1) & 3
.set OFFSET_CO, OFFSET_CO + 4
.endr
.set OFFSET_CO, 4 * MAX_FIR_ORDER
.rept \iir_taps
load CO, LOAD_REG, PCO, OFFSET_CO
.set LOAD_REG, (LOAD_REG + 1) & 3
.set OFFSET_CO, OFFSET_CO + 4
.endr
.endif
// Move mask/shift to final positions if necessary
// Need to do this after preloading, because in some cases we
// reuse the coefficient pointer register
.if SHUFFLE_SHIFT
mov SHIFT, ST0
.endif
.if SHUFFLE_MASK
mov MASK, ST1
.endif
// Begin loop
01:
.if TOTAL_TAPS == 0
// Things simplify a lot in this case
// In fact this could be pipelined further if it's worth it...
ldr ST0, [PSAMP]
subs I, I, #1
.if !\mask_minus1
and ST0, ST0, MASK
.endif
str ST0, [PST, #-4]!
str ST0, [PST, #4 * (MAX_BLOCKSIZE + MAX_FIR_ORDER)]
str ST0, [PSAMP], #4 * MAX_CHANNELS
bne 01b
.else
.if \fir_taps & 1
.set LOAD_REG, 1
.else
.set LOAD_REG, 0
.endif
.set LOAD_BANK, 0
.set FIR_REMAIN, \fir_taps
.set IIR_REMAIN, \iir_taps
.if FIR_REMAIN == 0 // only IIR terms
.set OFFSET_CO, 4 * MAX_FIR_ORDER
.set OFFSET_ST, 4 * (MAX_BLOCKSIZE + MAX_FIR_ORDER)
.else
.set OFFSET_CO, 0
.set OFFSET_ST, 0
.endif
.set MUL_REG, LOAD_REG
.set COUNTER, 0
.rept TOTAL_TAPS + 2
// Do load(s)
.if FIR_REMAIN != 0 || IIR_REMAIN != 0
.if COUNTER == 0
.if TOTAL_TAPS > 4
load CO, LOAD_REG, PCO, OFFSET_CO
.endif
load ST, LOAD_REG, PST, OFFSET_ST
inc 1
.elseif COUNTER == 1 && (\fir_taps & 1) == 0
.if TOTAL_TAPS > 4
load CO, LOAD_REG, PCO, OFFSET_CO
.endif
load ST, LOAD_REG, PST, OFFSET_ST
inc 1
.elseif LOAD_BANK == 0
.if TOTAL_TAPS > 4
.if FIR_REMAIN == 0 && IIR_REMAIN == 1
load CO, LOAD_REG, PCO, OFFSET_CO
.else
loadd CO, LOAD_REG, PCO, OFFSET_CO
.endif
.endif
.set LOAD_BANK, 1
.else
.if FIR_REMAIN == 0 && IIR_REMAIN == 1
load ST, LOAD_REG, PST, OFFSET_ST
inc 1
.else
loadd ST, LOAD_REG, PST, OFFSET_ST
inc 2
.endif
.set LOAD_BANK, 0
.endif
.endif
// Do interleaved multiplies, slightly delayed
.if COUNTER >= 2
multiply MUL_REG, COUNTER > 2, !\shift_0
.set MUL_REG, (MUL_REG + 1) & 3
.endif
.set COUNTER, COUNTER + 1
.endr
// Post-process the result of the multiplies
.if SPILL_SHIFT
ldr SHIFT, [sp, #9*4 + 0*4]
.endif
.if SPILL_MASK
ldr MASK, [sp, #9*4 + 1*4]
.endif
ldr ST2, [PSAMP]
subs I, I, #1
.if \shift_8
mov AC0, AC0, lsr #8
orr AC0, AC0, AC1, lsl #24
.elseif !\shift_0
rsb ST3, SHIFT, #32
mov AC0, AC0, lsr SHIFT
A orr AC0, AC0, AC1, lsl ST3
T mov AC1, AC1, lsl ST3
T orr AC0, AC0, AC1
.endif
.if \mask_minus1
add ST3, ST2, AC0
.else
add ST2, ST2, AC0
and ST3, ST2, MASK
sub ST2, ST3, AC0
.endif
str ST3, [PST, #-4]!
str ST2, [PST, #4 * (MAX_BLOCKSIZE + MAX_FIR_ORDER)]
str ST3, [PSAMP], #4 * MAX_CHANNELS
bne 01b
.endif
b 99f
.if DEFINED_SHIFT
.unreq SHIFT
.endif
.if DEFINED_MASK
.unreq MASK
.endif
.endm
.macro switch_on_fir_taps mask_minus1, shift_0, shift_8, iir_taps
A ldr pc, [pc, a3, LSL #2] // firorder is in range 0-(8-iir_taps)
T tbh [pc, a3, lsl #1]
0:
A .word 0, 70f, 71f, 72f, 73f, 74f
T .hword (70f - 0b) / 2, (71f - 0b) / 2, (72f - 0b) / 2, (73f - 0b) / 2, (74f - 0b) / 2
.if \iir_taps <= 3
A .word 75f
T .hword (75f - 0b) / 2
.if \iir_taps <= 2
A .word 76f
T .hword (76f - 0b) / 2
.if \iir_taps <= 1
A .word 77f
T .hword (77f - 0b) / 2
.if \iir_taps == 0
A .word 78f
T .hword (78f - 0b) / 2
.endif
.endif
.endif
.endif
70: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 0
71: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 1
72: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 2
73: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 3
74: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 4
.if \iir_taps <= 3
75: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 5
.if \iir_taps <= 2
76: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 6
.if \iir_taps <= 1
77: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 7
.if \iir_taps == 0
78: implement_filter \mask_minus1, \shift_0, \shift_8, \iir_taps, 8
.endif
.endif
.endif
.endif
.endm
.macro switch_on_iir_taps mask_minus1, shift_0, shift_8
A ldr pc, [pc, a4, LSL #2] // irorder is in range 0-4
T tbh [pc, a4, lsl #1]
0:
A .word 0, 60f, 61f, 62f, 63f, 64f
T .hword (60f - 0b) / 2, (61f - 0b) / 2, (62f - 0b) / 2, (63f - 0b) / 2, (64f - 0b) / 2
60: switch_on_fir_taps \mask_minus1, \shift_0, \shift_8, 0
61: switch_on_fir_taps \mask_minus1, \shift_0, \shift_8, 1
62: switch_on_fir_taps \mask_minus1, \shift_0, \shift_8, 2
63: switch_on_fir_taps \mask_minus1, \shift_0, \shift_8, 3
64: switch_on_fir_taps \mask_minus1, \shift_0, \shift_8, 4
.endm
/* void ff_mlp_filter_channel_arm(int32_t *state, const int32_t *coeff,
* int firorder, int iirorder,
* unsigned int filter_shift, int32_t mask,
* int blocksize, int32_t *sample_buffer);
*/
function ff_mlp_filter_channel_arm, export=1
push {v1-fp,lr}
add v1, sp, #9*4 // point at arguments on stack
ldm v1, {ST0,ST1,I,PSAMP}
cmp ST1, #-1
bne 30f
movs ST2, ST0, lsl #29 // shift is in range 0-15; we want to special-case 0 and 8
bne 20f
bcs 10f
switch_on_iir_taps 1, 1, 0
10: switch_on_iir_taps 1, 0, 1
20: switch_on_iir_taps 1, 0, 0
30: movs ST2, ST0, lsl #29 // shift is in range 0-15; we want to special-case 0 and 8
bne 50f
bcs 40f
switch_on_iir_taps 0, 1, 0
40: switch_on_iir_taps 0, 0, 1
50: switch_on_iir_taps 0, 0, 0
99: pop {v1-fp,pc}
endfunc
.unreq PST
.unreq PCO
.unreq AC0
.unreq AC1
.unreq CO0
.unreq CO1
.unreq CO2
.unreq CO3
.unreq ST0
.unreq ST1
.unreq ST2
.unreq ST3
.unreq I
.unreq PSAMP

36
libavcodec/arm/mlpdsp_init_arm.c
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@ -0,0 +1,36 @@
/*
* Copyright (c) 2014 RISC OS Open Ltd
* Author: Ben Avison <bavison@riscosopen.org>
*
* 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 <stdint.h>
#include "libavutil/arm/cpu.h"
#include "libavutil/attributes.h"
#include "libavcodec/mlpdsp.h"
void ff_mlp_filter_channel_arm(int32_t *state, const int32_t *coeff,
int firorder, int iirorder,
unsigned int filter_shift, int32_t mask,
int blocksize, int32_t *sample_buffer);
av_cold void ff_mlpdsp_init_arm(MLPDSPContext *c)
{
c->mlp_filter_channel = ff_mlp_filter_channel_arm;
}

2
libavcodec/mlpdsp.c
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@ -60,6 +60,8 @@ static void mlp_filter_channel(int32_t *state, const int32_t *coeff,
av_cold void ff_mlpdsp_init(MLPDSPContext *c) av_cold void ff_mlpdsp_init(MLPDSPContext *c)
{ {
c->mlp_filter_channel = mlp_filter_channel; c->mlp_filter_channel = mlp_filter_channel;
if (ARCH_ARM)
ff_mlpdsp_init_arm(c);
if (ARCH_X86) if (ARCH_X86)
ff_mlpdsp_init_x86(c); ff_mlpdsp_init_x86(c);
} }

1
libavcodec/mlpdsp.h
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@ -32,6 +32,7 @@ typedef struct MLPDSPContext {
} MLPDSPContext; } MLPDSPContext;
void ff_mlpdsp_init(MLPDSPContext *c); void ff_mlpdsp_init(MLPDSPContext *c);
void ff_mlpdsp_init_arm(MLPDSPContext *c);
void ff_mlpdsp_init_x86(MLPDSPContext *c); void ff_mlpdsp_init_x86(MLPDSPContext *c);
#endif /* AVCODEC_MLPDSP_H */ #endif /* AVCODEC_MLPDSP_H */

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