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Introduced ARM version of WebRtcSpl_SqrtFloor(). Function cycles reduced by ~ 30% in a real time VOE test in an android device (Nexus-S, ARMv7a).

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// Fritz, I added you as a reviewer for the assembly files, just as a warm-up for future storms. :-) The assembly code was from public domain and there's little to touch.
Review URL: https://webrtc-codereview.appspot.com/369017

git-svn-id: http://webrtc.googlecode.com/svn/trunk@1627 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
kma@webrtc.org 2012-02-07 17:15:15 +00:00
parent 9d9ad88ba5
commit 59f16ec993
5 changed files with 160 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/LICENSE_THIRD_PARTY
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@ -4,6 +4,8 @@ licenses than the one provided in the LICENSE file in the root of the source
tree.
Files governed by third party licenses:
common_audio/signal_processing/spl_sqrt_floor.c
common_audio/signal_processing/spl_sqrt_floor.s
modules/audio_coding/codecs/G711/main/source/g711.h
modules/audio_coding/codecs/G711/main/source/g711.c
modules/audio_coding/codecs/G722/main/source/g722_decode.h

9
src/common_audio/signal_processing/Android.mk
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@ -42,7 +42,6 @@ LOCAL_SRC_FILES := \
resample_by_2_internal.c \
resample_fractional.c \
spl_sqrt.c \
spl_sqrt_floor.c \
spl_version.c \
splitting_filter.c \
sqrt_of_one_minus_x_squared.c \
@ -75,6 +74,14 @@ LOCAL_SRC_FILES += \
filter_ar_fast_q12.c
endif
ifeq ($(TARGET_ARCH),arm)
LOCAL_SRC_FILES += \
spl_sqrt_floor.s
else
LOCAL_SRC_FILES += \
spl_sqrt_floor.c
endif
LOCAL_SHARED_LIBRARIES := libstlport
ifeq ($(TARGET_OS)-$(TARGET_SIMULATOR),linux-true)

71
src/common_audio/signal_processing/spl_sqrt_floor.c
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@ -1,21 +1,26 @@
/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/*
* This file contains the function WebRtcSpl_SqrtFloor().
* The description header can be found in signal_processing_library.h
* Written by Wilco Dijkstra, 1996. Refer to file LICENSE under
* trunk/third_party_mods/sqrt_floor.
*
* Minor modifications in code style for WebRTC, 2012.
*/
#include "signal_processing_library.h"
/*
* Algorithm:
* Successive approximation of the equation (root + delta) ^ 2 = N
* until delta < 1. If delta < 1 we have the integer part of SQRT (N).
* Use delta = 2^i for i = 15 .. 0.
*
* Output precision is 16 bits. Note for large input values (close to
* 0x7FFFFFFF), bit 15 (the highest bit of the low 16-bit half word)
* contains the MSB information (a non-sign value). Do with caution
* if you need to cast the output to int16_t type.
*
* If the input value is negative, it returns 0.
*/
#define WEBRTC_SPL_SQRT_ITER(N) \
try1 = root + (1 << (N)); \
if (value >= try1 << (N)) \
@ -24,30 +29,26 @@
root |= 2 << (N); \
}
// (out) Square root of input parameter
WebRtc_Word32 WebRtcSpl_SqrtFloor(WebRtc_Word32 value)
int32_t WebRtcSpl_SqrtFloor(int32_t value)
{
// new routine for performance, 4 cycles/bit in ARM
// output precision is 16 bits
int32_t root = 0, try1;
WebRtc_Word32 root = 0, try1;
WEBRTC_SPL_SQRT_ITER (15);
WEBRTC_SPL_SQRT_ITER (14);
WEBRTC_SPL_SQRT_ITER (13);
WEBRTC_SPL_SQRT_ITER (12);
WEBRTC_SPL_SQRT_ITER (11);
WEBRTC_SPL_SQRT_ITER (10);
WEBRTC_SPL_SQRT_ITER ( 9);
WEBRTC_SPL_SQRT_ITER ( 8);
WEBRTC_SPL_SQRT_ITER ( 7);
WEBRTC_SPL_SQRT_ITER ( 6);
WEBRTC_SPL_SQRT_ITER ( 5);
WEBRTC_SPL_SQRT_ITER ( 4);
WEBRTC_SPL_SQRT_ITER ( 3);
WEBRTC_SPL_SQRT_ITER ( 2);
WEBRTC_SPL_SQRT_ITER ( 1);
WEBRTC_SPL_SQRT_ITER ( 0);
WEBRTC_SPL_SQRT_ITER (15);
WEBRTC_SPL_SQRT_ITER (14);
WEBRTC_SPL_SQRT_ITER (13);
WEBRTC_SPL_SQRT_ITER (12);
WEBRTC_SPL_SQRT_ITER (11);
WEBRTC_SPL_SQRT_ITER (10);
WEBRTC_SPL_SQRT_ITER ( 9);
WEBRTC_SPL_SQRT_ITER ( 8);
WEBRTC_SPL_SQRT_ITER ( 7);
WEBRTC_SPL_SQRT_ITER ( 6);
WEBRTC_SPL_SQRT_ITER ( 5);
WEBRTC_SPL_SQRT_ITER ( 4);
WEBRTC_SPL_SQRT_ITER ( 3);
WEBRTC_SPL_SQRT_ITER ( 2);
WEBRTC_SPL_SQRT_ITER ( 1);
WEBRTC_SPL_SQRT_ITER ( 0);
return root >> 1;
return root >> 1;
}

88
src/common_audio/signal_processing/spl_sqrt_floor.s Normal file
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@ -0,0 +1,88 @@
@ Written by Wilco Dijkstra, 1996. Refer to file LICENSE under
@ trunk/third_party_mods/sqrt_floor.
@
@ Minor modifications in code style for WebRTC, 2012.
@ Output is bit-exact with the reference C code in spl_sqrt_floor.c.
@ Input : r0 32 bit unsigned integer
@ Output: r0 = INT (SQRT (r0)), precision is 16 bits
@ Registers touched: r1, r2
.global WebRtcSpl_SqrtFloor
.align 2
WebRtcSpl_SqrtFloor:
.fnstart
mov r1, #3 << 30
mov r2, #1 << 30
@ unroll for i = 0 .. 15
cmp r0, r2, ror #2 * 0
subhs r0, r0, r2, ror #2 * 0
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 1
subhs r0, r0, r2, ror #2 * 1
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 2
subhs r0, r0, r2, ror #2 * 2
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 3
subhs r0, r0, r2, ror #2 * 3
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 4
subhs r0, r0, r2, ror #2 * 4
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 5
subhs r0, r0, r2, ror #2 * 5
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 6
subhs r0, r0, r2, ror #2 * 6
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 7
subhs r0, r0, r2, ror #2 * 7
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 8
subhs r0, r0, r2, ror #2 * 8
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 9
subhs r0, r0, r2, ror #2 * 9
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 10
subhs r0, r0, r2, ror #2 * 10
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 11
subhs r0, r0, r2, ror #2 * 11
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 12
subhs r0, r0, r2, ror #2 * 12
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 13
subhs r0, r0, r2, ror #2 * 13
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 14
subhs r0, r0, r2, ror #2 * 14
adc r2, r1, r2, lsl #1
cmp r0, r2, ror #2 * 15
subhs r0, r0, r2, ror #2 * 15
adc r2, r1, r2, lsl #1
bic r0, r2, #3 << 30 @ for rounding add: cmp r0, r2 adc r2, #1
bx lr
.fnend

26
third_party_mods/sqrt_floor/LICENSE Normal file
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@ -0,0 +1,26 @@
The following email record is related to source files spl_sqrt_floor.c
and spl_sqrt_floor.s in trunk/src/common_audio/signal_processing/.
From: Wilco Dijkstra <Wilco.Dijkstra@ntlworld.com>
Date: Fri, Jun 24, 2011 at 3:20 AM
Subject: Re: sqrt routine
To: Kevin Ma <kma@google.com>
Hi Kevin,
Thanks for asking. Those routines are public domain (originally posted to
comp.sys.arm a long time ago), so you can use them freely for any purpose.
Cheers,
Wilco
----- Original Message -----
From: "Kevin Ma" <kma@google.com>
To: <Wilco.Dijkstra@ntlworld.com>
Sent: Thursday, June 23, 2011 11:44 PM
Subject: Fwd: sqrt routine
Hi Wilco,
I saw your sqrt routine from several web sites, including
http://www.finesse.demon.co.uk/steven/sqrt.html.
Just wonder if there's any copyright information with your Successive
approximation routines, or if I can freely use it for any purpose.
Thanks.
Kevin