The Tor Browser: media/libsoundtouch/src/sse_optimized.cpp@97036ab72558 (annotated)

media/libsoundtouch/src/sse_optimized.cpp@97036ab72558 (annotated)

media/libsoundtouch/src/sse_optimized.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 ////////////////////////////////////////////////////////////////////////////////
 ///
 /// SSE optimized routines for Pentium-III, Athlon-XP and later CPUs. All SSE
 /// optimized functions have been gathered into this single source
 /// code file, regardless to their class or original source code file, in order
 /// to ease porting the library to other compiler and processor platforms.
 ///
 /// The SSE-optimizations are programmed using SSE compiler intrinsics that
 /// are supported both by Microsoft Visual C++ and GCC compilers, so this file
 /// should compile with both toolsets.
 ///
 /// NOTICE: If using Visual Studio 6.0, you'll need to install the "Visual C++
 /// 6.0 processor pack" update to support SSE instruction set. The update is
 /// available for download at Microsoft Developers Network, see here:
 /// http://msdn.microsoft.com/en-us/vstudio/aa718349.aspx
 ///
 /// If the above URL is expired or removed, go to "http://msdn.microsoft.com" and
 /// perform a search with keywords "processor pack".
 ///
 /// Author        : Copyright (c) Olli Parviainen
 /// Author e-mail : oparviai 'at' iki.fi
 /// SoundTouch WWW: http://www.surina.net/soundtouch
 ///
 ////////////////////////////////////////////////////////////////////////////////
 //
 // Last changed  : $Date: 2014-01-07 12:25:40 -0600 (Tue, 07 Jan 2014) $
 // File revision : $Revision: 4 $
 //
 // $Id: sse_optimized.cpp 184 2014-01-07 18:25:40Z oparviai $
 //
 ////////////////////////////////////////////////////////////////////////////////
 //
 // License :
 //
 //  SoundTouch audio processing library
 //  Copyright (c) Olli Parviainen
 //
 //  This library 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.
 //
 //  This library 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 this library; if not, write to the Free Software
 //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 //
 ////////////////////////////////////////////////////////////////////////////////
 #include "cpu_detect.h"
 #include "STTypes.h"
 using namespace soundtouch;
 #ifdef SOUNDTOUCH_ALLOW_SSE
 // SSE routines available only with float sample type
 //////////////////////////////////////////////////////////////////////////////
 //
 // implementation of SSE optimized functions of class 'TDStretchSSE'
 //
 //////////////////////////////////////////////////////////////////////////////
 #include "TDStretch.h"
 #include <xmmintrin.h>
 #include <math.h>
 // Calculates cross correlation of two buffers
 double TDStretchSSE::calcCrossCorr(const float *pV1, const float *pV2, double &norm) const
 {
     int i;
     const float *pVec1;
     const __m128 *pVec2;
     __m128 vSum, vNorm;
     // Note. It means a major slow-down if the routine needs to tolerate
     // unaligned __m128 memory accesses. It's way faster if we can skip
     // unaligned slots and use _mm_load_ps instruction instead of _mm_loadu_ps.
     // This can mean up to ~ 10-fold difference (incl. part of which is
     // due to skipping every second round for stereo sound though).
     //
     // Compile-time define SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION is provided
     // for choosing if this little cheating is allowed.
 #ifdef SOUNDTOUCH_ALLOW_NONEXACT_SIMD_OPTIMIZATION
     // Little cheating allowed, return valid correlation only for
     // aligned locations, meaning every second round for stereo sound.
     #define _MM_LOAD    _mm_load_ps
     if (((ulongptr)pV1) & 15) return -1e50;    // skip unaligned locations
 #else
     // No cheating allowed, use unaligned load & take the resulting
     // performance hit.
     #define _MM_LOAD    _mm_loadu_ps
 #endif
     // ensure overlapLength is divisible by 8
     assert((overlapLength % 8) == 0);
     // Calculates the cross-correlation value between 'pV1' and 'pV2' vectors
     // Note: pV2 _must_ be aligned to 16-bit boundary, pV1 need not.
     pVec1 = (const float*)pV1;
     pVec2 = (const __m128*)pV2;
     vSum = vNorm = _mm_setzero_ps();
     // Unroll the loop by factor of 4 * 4 operations. Use same routine for
     // stereo & mono, for mono it just means twice the amount of unrolling.
     for (i = 0; i < channels * overlapLength / 16; i ++)
     {
         __m128 vTemp;
         // vSum += pV1[0..3] * pV2[0..3]
         vTemp = _MM_LOAD(pVec1);
         vSum  = _mm_add_ps(vSum,  _mm_mul_ps(vTemp ,pVec2[0]));
         vNorm = _mm_add_ps(vNorm, _mm_mul_ps(vTemp ,vTemp));
         // vSum += pV1[4..7] * pV2[4..7]
         vTemp = _MM_LOAD(pVec1 + 4);
         vSum  = _mm_add_ps(vSum, _mm_mul_ps(vTemp, pVec2[1]));
         vNorm = _mm_add_ps(vNorm, _mm_mul_ps(vTemp ,vTemp));
         // vSum += pV1[8..11] * pV2[8..11]
         vTemp = _MM_LOAD(pVec1 + 8);
         vSum  = _mm_add_ps(vSum, _mm_mul_ps(vTemp, pVec2[2]));
         vNorm = _mm_add_ps(vNorm, _mm_mul_ps(vTemp ,vTemp));
         // vSum += pV1[12..15] * pV2[12..15]
         vTemp = _MM_LOAD(pVec1 + 12);
         vSum  = _mm_add_ps(vSum, _mm_mul_ps(vTemp, pVec2[3]));
         vNorm = _mm_add_ps(vNorm, _mm_mul_ps(vTemp ,vTemp));
         pVec1 += 16;
         pVec2 += 4;
     }
     // return value = vSum[0] + vSum[1] + vSum[2] + vSum[3]
     float *pvNorm = (float*)&vNorm;
     norm = (pvNorm[0] + pvNorm[1] + pvNorm[2] + pvNorm[3]);
     float *pvSum = (float*)&vSum;
     return (double)(pvSum[0] + pvSum[1] + pvSum[2] + pvSum[3]) / sqrt(norm < 1e-9 ? 1.0 : norm);
     /* This is approximately corresponding routine in C-language yet without normalization:
     double corr, norm;
     uint i;
     // Calculates the cross-correlation value between 'pV1' and 'pV2' vectors
     corr = norm = 0.0;
     for (i = 0; i < channels * overlapLength / 16; i ++)
     {
         corr += pV1[0] * pV2[0] +
                 pV1[1] * pV2[1] +
                 pV1[2] * pV2[2] +
                 pV1[3] * pV2[3] +
                 pV1[4] * pV2[4] +
                 pV1[5] * pV2[5] +
                 pV1[6] * pV2[6] +
                 pV1[7] * pV2[7] +
                 pV1[8] * pV2[8] +
                 pV1[9] * pV2[9] +
                 pV1[10] * pV2[10] +
                 pV1[11] * pV2[11] +
                 pV1[12] * pV2[12] +
                 pV1[13] * pV2[13] +
                 pV1[14] * pV2[14] +
                 pV1[15] * pV2[15];
     for (j = 0; j < 15; j ++) norm += pV1[j] * pV1[j];
         pV1 += 16;
         pV2 += 16;
     }
     return corr / sqrt(norm);
     */
 }
 double TDStretchSSE::calcCrossCorrAccumulate(const float *pV1, const float *pV2, double &norm) const
 {
     // call usual calcCrossCorr function because SSE does not show big benefit of
     // accumulating "norm" value, and also the "norm" rolling algorithm would get
     // complicated due to SSE-specific alignment-vs-nonexact correlation rules.
     return calcCrossCorr(pV1, pV2, norm);
 }
 //////////////////////////////////////////////////////////////////////////////
 //
 // implementation of SSE optimized functions of class 'FIRFilter'
 //
 //////////////////////////////////////////////////////////////////////////////
 #include "FIRFilter.h"
 FIRFilterSSE::FIRFilterSSE() : FIRFilter()
 {
     filterCoeffsAlign = NULL;
     filterCoeffsUnalign = NULL;
 }
 FIRFilterSSE::~FIRFilterSSE()
 {
     delete[] filterCoeffsUnalign;
     filterCoeffsAlign = NULL;
     filterCoeffsUnalign = NULL;
 }
 // (overloaded) Calculates filter coefficients for SSE routine
 void FIRFilterSSE::setCoefficients(const float *coeffs, uint newLength, uint uResultDivFactor)
 {
     uint i;
     float fDivider;
     FIRFilter::setCoefficients(coeffs, newLength, uResultDivFactor);
     // Scale the filter coefficients so that it won't be necessary to scale the filtering result
     // also rearrange coefficients suitably for SSE
     // Ensure that filter coeffs array is aligned to 16-byte boundary
     delete[] filterCoeffsUnalign;
     filterCoeffsUnalign = new float[2 * newLength + 4];
     filterCoeffsAlign = (float *)SOUNDTOUCH_ALIGN_POINTER_16(filterCoeffsUnalign);
     fDivider = (float)resultDivider;
     // rearrange the filter coefficients for mmx routines
     for (i = 0; i < newLength; i ++)
     {
         filterCoeffsAlign[2 * i + 0] =
         filterCoeffsAlign[2 * i + 1] = coeffs[i + 0] / fDivider;
     }
 }
 // SSE-optimized version of the filter routine for stereo sound
 uint FIRFilterSSE::evaluateFilterStereo(float *dest, const float *source, uint numSamples) const
 {
     int count = (int)((numSamples - length) & (uint)-2);
     int j;
     assert(count % 2 == 0);
     if (count < 2) return 0;
     assert(source != NULL);
     assert(dest != NULL);
     assert((length % 8) == 0);
     assert(filterCoeffsAlign != NULL);
     assert(((ulongptr)filterCoeffsAlign) % 16 == 0);
     // filter is evaluated for two stereo samples with each iteration, thus use of 'j += 2'
     for (j = 0; j < count; j += 2)
     {
         const float *pSrc;
         const __m128 *pFil;
         __m128 sum1, sum2;
         uint i;
         pSrc = (const float*)source;              // source audio data
         pFil = (const __m128*)filterCoeffsAlign;  // filter coefficients. NOTE: Assumes coefficients
                                                   // are aligned to 16-byte boundary
         sum1 = sum2 = _mm_setzero_ps();
         for (i = 0; i < length / 8; i ++)
         {
             // Unroll loop for efficiency & calculate filter for 2*2 stereo samples
             // at each pass
             // sum1 is accu for 2*2 filtered stereo sound data at the primary sound data offset
             // sum2 is accu for 2*2 filtered stereo sound data for the next sound sample offset.
             sum1 = _mm_add_ps(sum1, _mm_mul_ps(_mm_loadu_ps(pSrc)    , pFil[0]));
             sum2 = _mm_add_ps(sum2, _mm_mul_ps(_mm_loadu_ps(pSrc + 2), pFil[0]));
             sum1 = _mm_add_ps(sum1, _mm_mul_ps(_mm_loadu_ps(pSrc + 4), pFil[1]));
             sum2 = _mm_add_ps(sum2, _mm_mul_ps(_mm_loadu_ps(pSrc + 6), pFil[1]));
             sum1 = _mm_add_ps(sum1, _mm_mul_ps(_mm_loadu_ps(pSrc + 8) ,  pFil[2]));
             sum2 = _mm_add_ps(sum2, _mm_mul_ps(_mm_loadu_ps(pSrc + 10), pFil[2]));
             sum1 = _mm_add_ps(sum1, _mm_mul_ps(_mm_loadu_ps(pSrc + 12), pFil[3]));
             sum2 = _mm_add_ps(sum2, _mm_mul_ps(_mm_loadu_ps(pSrc + 14), pFil[3]));
             pSrc += 16;
             pFil += 4;
         }
         // Now sum1 and sum2 both have a filtered 2-channel sample each, but we still need
         // to sum the two hi- and lo-floats of these registers together.
         // post-shuffle & add the filtered values and store to dest.
         _mm_storeu_ps(dest, _mm_add_ps(
                     _mm_shuffle_ps(sum1, sum2, _MM_SHUFFLE(1,0,3,2)),   // s2_1 s2_0 s1_3 s1_2
                     _mm_shuffle_ps(sum1, sum2, _MM_SHUFFLE(3,2,1,0))    // s2_3 s2_2 s1_1 s1_0
                     ));
         source += 4;
         dest += 4;
     }
     // Ideas for further improvement:
     // 1. If it could be guaranteed that 'source' were always aligned to 16-byte
     //    boundary, a faster aligned '_mm_load_ps' instruction could be used.
     // 2. If it could be guaranteed that 'dest' were always aligned to 16-byte
     //    boundary, a faster '_mm_store_ps' instruction could be used.
     return (uint)count;
     /* original routine in C-language. please notice the C-version has differently
        organized coefficients though.
     double suml1, suml2;
     double sumr1, sumr2;
     uint i, j;
     for (j = 0; j < count; j += 2)
     {
         const float *ptr;
         const float *pFil;
         suml1 = sumr1 = 0.0;
         suml2 = sumr2 = 0.0;
         ptr = src;
         pFil = filterCoeffs;
         for (i = 0; i < lengthLocal; i ++)
         {
             // unroll loop for efficiency.
             suml1 += ptr[0] * pFil[0] +
                      ptr[2] * pFil[2] +
                      ptr[4] * pFil[4] +
                      ptr[6] * pFil[6];
             sumr1 += ptr[1] * pFil[1] +
                      ptr[3] * pFil[3] +
                      ptr[5] * pFil[5] +
                      ptr[7] * pFil[7];
             suml2 += ptr[8] * pFil[0] +
                      ptr[10] * pFil[2] +
                      ptr[12] * pFil[4] +
                      ptr[14] * pFil[6];
             sumr2 += ptr[9] * pFil[1] +
                      ptr[11] * pFil[3] +
                      ptr[13] * pFil[5] +
                      ptr[15] * pFil[7];
             ptr += 16;
             pFil += 8;
         }
         dest[0] = (float)suml1;
         dest[1] = (float)sumr1;
         dest[2] = (float)suml2;
         dest[3] = (float)sumr2;
         src += 4;
         dest += 4;
     }
     */
 }
 #endif  // SOUNDTOUCH_ALLOW_SSE

The Tor Browser / annotate

media/libsoundtouch/src/sse_optimized.cpp@97036ab72558 (annotated)

media/libsoundtouch/src/sse_optimized.cpp