[FFmpeg-devel] [PATCH 1/5] truehd: add hand-scheduled ARM asm version of mlp_filter_channel.
Ben Avison
bavison at riscosopen.org
Thu Mar 20 19:59:14 CET 2014
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.
---
libavcodec/arm/Makefile | 2 +
libavcodec/arm/mlpdsp_arm.S | 433 ++++++++++++++++++++++++++++++++++++++
libavcodec/arm/mlpdsp_init_arm.c | 36 +++
libavcodec/mlpdsp.c | 2 +
libavcodec/mlpdsp.h | 1 +
5 files changed, 474 insertions(+), 0 deletions(-)
create mode 100644 libavcodec/arm/mlpdsp_arm.S
create mode 100644 libavcodec/arm/mlpdsp_init_arm.c
diff --git a/libavcodec/arm/Makefile b/libavcodec/arm/Makefile
index a8446b2..ba673b1 100644
--- a/libavcodec/arm/Makefile
+++ b/libavcodec/arm/Makefile
@@ -22,6 +22,8 @@ OBJS-$(CONFIG_H264PRED) += arm/h264pred_init_arm.o
OBJS-$(CONFIG_H264QPEL) += arm/h264qpel_init_arm.o
OBJS-$(CONFIG_HPELDSP) += arm/hpeldsp_init_arm.o \
arm/hpeldsp_arm.o
+OBJS-$(CONFIG_MLP_DECODER) += arm/mlpdsp_init_arm.o \
+ arm/mlpdsp_arm.o
OBJS-$(CONFIG_MPEGAUDIODSP) += arm/mpegaudiodsp_init_arm.o
OBJS-$(CONFIG_MPEGVIDEO) += arm/mpegvideo_arm.o
OBJS-$(CONFIG_NEON_CLOBBER_TEST) += arm/neontest.o
diff --git a/libavcodec/arm/mlpdsp_arm.S b/libavcodec/arm/mlpdsp_arm.S
new file mode 100644
index 0000000..615819d
--- /dev/null
+++ b/libavcodec/arm/mlpdsp_arm.S
@@ -0,0 +1,433 @@
+/*
+ * Copyright (c) 2014 RISC OS Open Ltd
+ * Author: Ben Avison <bavison at 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
diff --git a/libavcodec/arm/mlpdsp_init_arm.c b/libavcodec/arm/mlpdsp_init_arm.c
new file mode 100644
index 0000000..9a14815
--- /dev/null
+++ b/libavcodec/arm/mlpdsp_init_arm.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2014 RISC OS Open Ltd
+ * Author: Ben Avison <bavison at 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;
+}
diff --git a/libavcodec/mlpdsp.c b/libavcodec/mlpdsp.c
index b413e86..4b403b8 100644
--- a/libavcodec/mlpdsp.c
+++ b/libavcodec/mlpdsp.c
@@ -60,6 +60,8 @@ static void mlp_filter_channel(int32_t *state, const int32_t *coeff,
av_cold void ff_mlpdsp_init(MLPDSPContext *c)
{
c->mlp_filter_channel = mlp_filter_channel;
+ if (ARCH_ARM)
+ ff_mlpdsp_init_arm(c);
if (ARCH_X86)
ff_mlpdsp_init_x86(c);
}
diff --git a/libavcodec/mlpdsp.h b/libavcodec/mlpdsp.h
index 84a8aa3..129bcfe 100644
--- a/libavcodec/mlpdsp.h
+++ b/libavcodec/mlpdsp.h
@@ -32,6 +32,7 @@ typedef struct MLPDSPContext {
} MLPDSPContext;
void ff_mlpdsp_init(MLPDSPContext *c);
+void ff_mlpdsp_init_arm(MLPDSPContext *c);
void ff_mlpdsp_init_x86(MLPDSPContext *c);
#endif /* AVCODEC_MLPDSP_H */
--
1.7.5.4
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