From f4774bf5bf8fff2b45a6cee8e0b064b560b45809 Mon Sep 17 00:00:00 2001
From: Andree Buschmann <AndreeBuschmann@t-online.de>
Date: Sat, 29 Aug 2009 19:44:27 +0000
Subject: Submit interim version of FS#10565. Performance optimization of
 atrac3 decoder for ARM. Introduce ASM routines for multiplications and two
 synthesis loops, refactured parts of synthesis and windowing. Speeds up
 decoding by a factor of 2.4 on PP502x.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22548 a1c6a512-1295-4272-9138-f99709370657
---
 apps/codecs/libatrac/SOURCES            |   3 +
 apps/codecs/libatrac/atrac3.c           | 136 +++++++++++++++++++++++--------
 apps/codecs/libatrac/atrac3_arm.S       | 137 ++++++++++++++++++++++++++++++++
 apps/codecs/libatrac/atrac3data_fixed.h | 121 +++++++---------------------
 apps/codecs/libatrac/fixp_math.h        |  92 ++++++++++++++++-----
 5 files changed, 343 insertions(+), 146 deletions(-)
 create mode 100755 apps/codecs/libatrac/atrac3_arm.S

diff --git a/apps/codecs/libatrac/SOURCES b/apps/codecs/libatrac/SOURCES
index 972f9621fc..5a033c1732 100644
--- a/apps/codecs/libatrac/SOURCES
+++ b/apps/codecs/libatrac/SOURCES
@@ -1,2 +1,5 @@
 atrac3.c
+#if defined(CPU_ARM)
+atrac3_arm.S
+#endif
 ../lib/ffmpeg_bitstream.c
diff --git a/apps/codecs/libatrac/atrac3.c b/apps/codecs/libatrac/atrac3.c
index 47a63cae30..9ea2be8775 100644
--- a/apps/codecs/libatrac/atrac3.c
+++ b/apps/codecs/libatrac/atrac3.c
@@ -67,6 +67,101 @@ static inline int16_t av_clip_int16(int a)
 static int32_t          qmf_window[48] IBSS_ATTR;
 static VLC              spectral_coeff_tab[7];
 static channel_unit     channel_units[2];
+
+/**
+ * Matrixing within quadrature mirror synthesis filter.
+ *
+ * @param p3        output buffer
+ * @param inlo      lower part of spectrum
+ * @param inhi      higher part of spectrum
+ * @param nIn       size of spectrum buffer
+ */
+ 
+#if defined(CPU_ARM)
+    extern void 
+    atrac3_iqmf_matrixing(int32_t *p3,
+                          int32_t *inlo,
+                          int32_t *inhi,
+                          unsigned int nIn);
+#else
+    static inline void
+    atrac3_iqmf_matrixing(int32_t *p3,
+                          int32_t *inlo,
+                          int32_t *inhi,
+                          unsigned int nIn)
+    {
+        for(i=0; i<nIn; i+=2){
+            p3[2*i+0] = inlo[i  ] + inhi[i  ];
+            p3[2*i+1] = inlo[i  ] - inhi[i  ];
+            p3[2*i+2] = inlo[i+1] + inhi[i+1];
+            p3[2*i+3] = inlo[i+1] - inhi[i+1];
+        }
+    }
+#endif
+
+/**
+ * Matrixing within quadrature mirror synthesis filter.
+ *
+ * @param out       output buffer
+ * @param in        input buffer
+ * @param win       windowing coefficients
+ * @param nIn       size of spectrum buffer
+ */
+ 
+#if defined(CPU_ARM)
+    extern void
+    atrac3_iqmf_dewindowing(int32_t *out,
+                            int32_t *in,
+                            int32_t *win,
+                            unsigned int nIn);
+#else
+    static inline void
+    atrac3_iqmf_dewindowing(int32_t *out,
+                            int32_t *in,
+                            int32_t *win,
+                            unsigned int nIn)
+    {
+        int32_t i, j, s1, s2;
+        
+        for (j = nIn; j != 0; j--) {
+            /* i=0 */
+            s1 = fixmul31(win[0], in[0]);
+            s2 = fixmul31(win[1], in[1]);
+    
+            /* i=2..46 */
+            for (i = 2; i < 48; i += 2) {
+                s1 += fixmul31(win[i  ], in[i  ]);
+                s2 += fixmul31(win[i+1], in[i+1]);
+            }
+    
+            out[0] = s2;
+            out[1] = s1;
+    
+            in += 2;
+            out += 2;
+        }
+    }
+#endif
+
+/**
+ * IMDCT windowing.
+ *
+ * @param buffer        sample buffer
+ * @param win           window coefficients
+ */
+ 
+static inline void
+atrac3_imdct_windowing(int32_t *buffer,
+                       const int32_t *win)
+{
+    int32_t i;
+    /* win[0..127] = win[511..384], win[128..383] = 1 */
+    for(i = 0; i<128; i++) {
+        buffer[    i] = fixmul31(win[i], buffer[    i]);
+        buffer[511-i] = fixmul31(win[i], buffer[511-i]);
+    }
+}
+
 /**
  * Quadrature mirror synthesis filter.
  *
@@ -77,42 +172,19 @@ static channel_unit     channel_units[2];
  * @param delayBuf  delayBuf buffer
  * @param temp      temp buffer
  */
+ 
 static void iqmf (int32_t *inlo, int32_t *inhi, unsigned int nIn, int32_t *pOut, int32_t *delayBuf, int32_t *temp)
 {
-    unsigned int   i, j;
-    int32_t   *p1, *p3;
-
+    /* Restore the delay buffer */
     memcpy(temp, delayBuf, 46*sizeof(int32_t));
 
-    p3 = temp + 46;
+    /* loop1: matrixing */
+    atrac3_iqmf_matrixing(temp + 46, inlo, inhi, nIn);
 
-    /* loop1 */
-    for(i=0; i<nIn; i+=2){
-        p3[2*i+0] = inlo[i  ] + inhi[i  ];
-        p3[2*i+1] = inlo[i  ] - inhi[i  ];
-        p3[2*i+2] = inlo[i+1] + inhi[i+1];
-        p3[2*i+3] = inlo[i+1] - inhi[i+1];
-    }
-
-    /* loop2 */
-    p1 = temp;
-    for (j = nIn; j != 0; j--) {
-        int32_t s1 = 0;
-        int32_t s2 = 0;
+    /* loop2: dewindowing */
+    atrac3_iqmf_dewindowing(pOut, temp, qmf_window, nIn);
 
-        for (i = 0; i < 48; i += 2) {
-            s1 += fixmul31(p1[i], qmf_window[i]);
-            s2 += fixmul31(p1[i+1], qmf_window[i+1]);
-        }
-
-        pOut[0] = s2;
-        pOut[1] = s1;
-
-        p1 += 2;
-        pOut += 2;
-    }
-
-    /* Update the delay buffer. */
+    /* Save the delay buffer */
     memcpy(delayBuf, temp + (nIn << 1), 46*sizeof(int32_t));
 }
 
@@ -146,9 +218,7 @@ static void IMLT(int32_t *pInput, int32_t *pOutput, int odd_band)
     mdct_backward(512, pInput, pOutput);
 
     /* Windowing. */
-    for(i = 0; i<512; i++)
-        pOutput[i] = fixmul31(pOutput[i], window_lookup[i]);
-
+    atrac3_imdct_windowing(pOutput, window_lookup);
 }
 
 
diff --git a/apps/codecs/libatrac/atrac3_arm.S b/apps/codecs/libatrac/atrac3_arm.S
new file mode 100755
index 0000000000..be8b2a0e0e
--- /dev/null
+++ b/apps/codecs/libatrac/atrac3_arm.S
@@ -0,0 +1,137 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id: 
+ *
+ * Copyright (C) 2009 by Andree Buschmann
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+    .section .text, "ax", %progbits
+
+/****************************************************************************
+ * void atrac3_iqmf_matrixing(int32_t *dest, 
+ *                            int32_t *inlo, 
+ *                            int32_t *inhi, 
+ *                            unsigned int count);
+ * 
+ * Matrixing step within iqmf of atrac3 synthesis. Reference implementation:
+ *
+ * for(i=0; i<counter; i+=2){
+ *      dest[2*i+0] = inlo[i  ] + inhi[i  ];
+ *      dest[2*i+1] = inlo[i  ] - inhi[i  ];
+ *      dest[2*i+2] = inlo[i+1] + inhi[i+1];
+ *      dest[2*i+3] = inlo[i+1] - inhi[i+1];
+ * }
+ * Note: r12 is a scratch register and can be used without restorage.
+ ****************************************************************************/
+    .align  2
+    .global atrac3_iqmf_matrixing
+    .type   atrac3_iqmf_matrixing, %function
+
+atrac3_iqmf_matrixing:
+    /* r0 = dest */
+    /* r1 = inlo */
+    /* r2 = inhi */
+    /* r3 = counter */
+    stmfd   sp!, {r4-r9, lr}       /* save non-scratch registers */
+    
+.iqmf_matrixing_loop:
+    ldmia r1!, { r4, r6, r8, r12}   /* load inlo[0...3] */
+    ldmia r2!, { r5, r7, r9, lr }   /* load inhi[0...3] */
+    add   r4, r4, r5                /* r4  = inlo[0] + inhi[0] */
+    sub   r5, r4, r5, asl #1        /* r5  = inlo[0] - inhi[0] */
+    add   r6, r6, r7                /* r6  = inlo[1] + inhi[1] */
+    sub   r7, r6, r7, asl #1        /* r7  = inlo[1] - inhi[1] */
+    add   r8, r8, r9                /* r8  = inlo[2] + inhi[2] */
+    sub   r9, r8, r9, asl #1        /* r9  = inlo[2] - inhi[2] */
+    add   r12, r12, lr              /* r12 = inlo[3] + inhi[3] */
+    sub   lr , r12, lr, asl #1      /* lr  = inlo[3] - inhi[3] */
+    stmia r0!, {r4-r9, r12, lr}     /* store results to dest */
+    subs r3, r3, #4                 /* counter -= 4 */
+    bgt .iqmf_matrixing_loop
+    
+    ldmfd   sp!, {r4-r9, pc}       /* restore registers */
+
+.atrac3_iqmf_matrixing_end:
+    .size   atrac3_iqmf_matrixing,.atrac3_iqmf_matrixing_end-atrac3_iqmf_matrixing
+
+    
+/****************************************************************************
+ * atrac3_iqmf_dewindowing(int32_t *out,
+ *                         int32_t *in,
+ *                         int32_t *win,
+ *                         unsigned int nIn);
+ * 
+ * Dewindowing step within iqmf of atrac3 synthesis. Reference implementation:
+ *
+ * for (j = nIn; j != 0; j--) {
+ *          s1 = fixmul32(in[0], win[0]);
+ *          s2 = fixmul32(in[1], win[1]);
+ *          for (i = 2; i < 48; i += 2) {
+ *              s1 += fixmul32(in[i  ], win[i  ]);
+ *              s2 += fixmul32(in[i+1], win[i+1]);
+ *          }
+ *          out[0] = s2 << 1;
+ *          out[1] = s1 << 1;
+ *          in += 2;
+ *          out += 2;
+ *      }
+ * Note: r12 is a scratch register and can be used without restorage.
+ ****************************************************************************/
+    .align  2
+    .global atrac3_iqmf_dewindowing
+    .type   atrac3_iqmf_dewindowing, %function
+    
+atrac3_iqmf_dewindowing:
+    /* r0 = dest */
+    /* r1 = input samples */
+    /* r2 = window coefficients */
+    /* r3 = counter */
+    stmfd   sp!, {r4-r10, lr}       /* save non-scratch registers */
+    
+.iqmf_dewindow_outer_loop:          /* outer loop 0...counter-1 */
+
+    ldmia r2!, {r5, r6}             /* load win[0..1] */
+    ldmia r1!, {r7, r8}             /* load in[0..1] */
+    smull lr , r10, r5, r7          /* s1 = win[0] * in[0] */
+    smull r12, r9 , r6, r8          /* s2 = win[1] * in[1] */
+
+    mov r4, #46                     /* r4 = 46 */
+.iqmf_dewindow_inner_loop:          /* inner loop i=2...48 */
+    ldmia r2!, {r5, r6}             /* load win[i...i+1] */
+    ldmia r1!, {r7, r8}             /* load in[i...i+1] */
+    smlal lr , r10, r5, r7          /* s1 = win[i  ] * in[i  ] */
+    smlal r12, r9 , r6, r8          /* s2 = win[i+1] * in[i+1] */
+
+    subs r4, r4, #2                 /* inner loop -= 2*/
+    bgt .iqmf_dewindow_inner_loop
+
+    mov   lr , lr , lsr #31
+    orr   r10, lr , r10, lsl #1     /* s1 = low>>31 || hi<<1 */
+    mov   r12, r12, lsr #31
+    orr   r9 , r12, r9 , lsl #1     /* s2 = low>>31 || hi<<1 */
+
+    stmia r0!, {r9, r10}            /* store result out[0]=s2, out[1]=s1 */
+    sub   r1, r1, #184              /* roll back 64 entries = 184 bytes */
+    sub   r2, r2, #192              /* roll back 48 entries = 192 bytes = win[0] */
+
+    subs r3, r3, #1                 /* outer loop -= 1 */
+    bgt .iqmf_dewindow_outer_loop
+    
+    ldmfd   sp!, {r4-r10, pc}       /* restore registers */
+    
+.atrac3_iqmf_dewindowing_end:
+    .size   atrac3_iqmf_dewindowing,.atrac3_iqmf_dewindowing_end-atrac3_iqmf_dewindowing
diff --git a/apps/codecs/libatrac/atrac3data_fixed.h b/apps/codecs/libatrac/atrac3data_fixed.h
index 561c45a87d..f0924a5190 100644
--- a/apps/codecs/libatrac/atrac3data_fixed.h
+++ b/apps/codecs/libatrac/atrac3data_fixed.h
@@ -22,102 +22,39 @@ static const int32_t SFTable_fixed[64] ICONST_ATTR = {
 };
 
 /* transform data */
-/* floating point values scaled by 2^31  */
+/* floating point values scaled by 2^31 */
 static const int32_t qmf_48tap_half_fix[24] ICONST_ATTR = {
-    0xffff855e, 0xfffcfbca, 0xfffe28eb, 0x9de6b,    0x7f028,    0xffe40d08, 
-    0xffeef140, 0x42a692,   0x19ab1f,   0xff75dec7, 0xffe738f5, 0x100e928, 
-    0xfffdfedf, 0xfe478b84, 0x50b279,   0x2c83f88,  0xff005ad7, 0xfba2ee80, 
-    0x2685970,  0x6f42798,  0xfa6b6f10, 0xf3475f80, 0x10e7f7c0, 0x3b6c44c0 
+    0xffff855e, 0xfffcfbca, 0xfffe28eb, 0x0009de6b, 0x0007f028, 0xffe40d08,
+    0xffeef140, 0x0042a692, 0x0019ab1f, 0xff75dec7, 0xffe738f5, 0x0100e928,
+    0xfffdfedf, 0xfe478b84, 0x0050b279, 0x02c83f88, 0xff005ad7, 0xfba2ee80,
+    0x02685970, 0x06f42798, 0xfa6b6f10, 0xf3475f80, 0x10e7f7c0, 0x3b6c44c0
 };
 
 /* mdct window scaled by 2^31 */
-static const int32_t window_lookup[512] ICONST_ATTR  = {
-    0xffffb10c, 0xfffd394b, 0xfff8494f, 0xfff0e025, 0xffe6fc5f, 0xffda9c15, 
-    0xffcbbce6, 0xffba5bf4, 0xffa675e8, 0xff9006f0, 0xff770aba, 0xff5b7c7e, 
-    0xff3d56f2, 0xff1c9452, 0xfef92e59, 0xfed31e45, 0xfeaa5cd5, 0xfe7ee247, 
-    0xfe50a657, 0xfe1fa041, 0xfdebc6c1, 0xfdb5100d, 0xfd7b71d5, 0xfd3ee149, 
-    0xfcff5311, 0xfcbcbb49, 0xfc770d99, 0xfc2e3d15, 0xfbe23c39, 0xfb92fd29, 
-    0xfb407141, 0xfaea8989, 0xfa913661, 0xfa3467b1, 0xf9d40cd9, 0xf9701499, 
-    0xf9086d41, 0xf89d04a9, 0xf82dc7f1, 0xf7baa3e1, 0xf74384b1, 0xf6c85611, 
-    0xf6490321, 0xf5c576b1, 0xf53d9b21, 0xf4b15a01, 0xf4209ce1, 0xf38b4c71, 
-    0xf2f15171, 0xf2529411, 0xf1aefbf1, 0xf10670a1, 0xf058d941, 0xefa61cc1, 
-    0xeeee21c1, 0xee30cec1, 0xed6e0a41, 0xeca5ba61, 0xebd7c5c1, 0xeb041241, 
-    0xea2a8601, 0xe94b0861, 0xe8657f61, 0xe779d241, 0xe687e861, 0xe58fa9e1, 
-    0xe490fec1, 0xe38bd101, 0xe28009c1, 0xe16d93e1, 0xe0545ba1, 0xdf344dc1, 
-    0xde0d5881, 0xdcdf6bc1, 0xdbaa7801, 0xda6e70c1, 0xd92b4ac1, 0xd7e0fc81, 
-    0xd68f7ec1, 0xd536cd41, 0xd3d6e5c1, 0xd26fc901, 0xd10179c1, 0xcf8bff41, 
-    0xce0f6301, 0xcc8bb241, 0xcb00fdc1, 0xc96f5b01, 0xc7d6e141, 0xc637af41, 
-    0xc491e4c1, 0xc2e5a801, 0xc1332401, 0xbf7a8701, 0xbdbc0681, 0xbbf7da01, 
-    0xba2e4181, 0xb85f7f81, 0xb68bde01, 0xb4b3a981, 0xb2d73781, 0xb0f6df01, 
-    0xaf12ff01, 0xad2bfa81, 0xab423981, 0xa9562981, 0xa7683c01, 0xa578e701, 
-    0xa388a681, 0xa197f801, 0x9fa75e81, 0x9db75f01, 0x9bc88201, 0x99db5301, 
-    0x97f06001, 0x96083601, 0x94236601, 0x92427f81, 0x90661481, 0x8e8eb481, 
-    0x8cbced01, 0x8af14d81, 0x892c5f81, 0x876eab01, 0x85b8b681, 0x840b0301, 
-    0x82660c01, 0x80ca4a01, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 0x80000000, 
-    0x80ca4a01, 0x82660c01, 0x840b0301, 0x85b8b681, 0x876eab01, 0x892c5f81, 
-    0x8af14d81, 0x8cbced01, 0x8e8eb481, 0x90661481, 0x92427f81, 0x94236601, 
-    0x96083601, 0x97f06001, 0x99db5301, 0x9bc88201, 0x9db75f01, 0x9fa75e81, 
-    0xa197f801, 0xa388a681, 0xa578e701, 0xa7683c01, 0xa9562981, 0xab423981, 
-    0xad2bfa81, 0xaf12ff01, 0xb0f6df01, 0xb2d73781, 0xb4b3a981, 0xb68bde01, 
-    0xb85f7f81, 0xba2e4181, 0xbbf7da01, 0xbdbc0681, 0xbf7a8701, 0xc1332401, 
-    0xc2e5a801, 0xc491e4c1, 0xc637af41, 0xc7d6e141, 0xc96f5b01, 0xcb00fdc1, 
-    0xcc8bb241, 0xce0f6301, 0xcf8bff41, 0xd10179c1, 0xd26fc901, 0xd3d6e5c1, 
-    0xd536cd41, 0xd68f7ec1, 0xd7e0fc81, 0xd92b4ac1, 0xda6e70c1, 0xdbaa7801, 
-    0xdcdf6bc1, 0xde0d5881, 0xdf344dc1, 0xe0545ba1, 0xe16d93e1, 0xe28009c1, 
-    0xe38bd101, 0xe490fec1, 0xe58fa9e1, 0xe687e861, 0xe779d241, 0xe8657f61, 
-    0xe94b0861, 0xea2a8601, 0xeb041241, 0xebd7c5c1, 0xeca5ba61, 0xed6e0a41, 
-    0xee30cec1, 0xeeee21c1, 0xefa61cc1, 0xf058d941, 0xf10670a1, 0xf1aefbf1, 
-    0xf2529411, 0xf2f15171, 0xf38b4c71, 0xf4209ce1, 0xf4b15a01, 0xf53d9b21, 
-    0xf5c576b1, 0xf6490321, 0xf6c85611, 0xf74384b1, 0xf7baa3e1, 0xf82dc7f1, 
-    0xf89d04a9, 0xf9086d41, 0xf9701499, 0xf9d40cd9, 0xfa3467b1, 0xfa913661, 
-    0xfaea8989, 0xfb407141, 0xfb92fd29, 0xfbe23c39, 0xfc2e3d15, 0xfc770d99, 
-    0xfcbcbb49, 0xfcff5311, 0xfd3ee149, 0xfd7b71d5, 0xfdb5100d, 0xfdebc6c1, 
-    0xfe1fa041, 0xfe50a657, 0xfe7ee247, 0xfeaa5cd5, 0xfed31e45, 0xfef92e59, 
-    0xff1c9452, 0xff3d56f2, 0xff5b7c7e, 0xff770aba, 0xff9006f0, 0xffa675e8, 
-    0xffba5bf4, 0xffcbbce6, 0xffda9c15, 0xffe6fc5f, 0xfff0e025, 0xfff8494f, 
-    0xfffd394b, 0xffffb10c, 
+/* Remark: The preceding sign corrects the sign of the hexadecimal values */
+static const int32_t window_lookup[128] ICONST_ATTR  = {
+    -0xffffb10c, -0xfffd394b, -0xfff8494f, -0xfff0e025, -0xffe6fc5f, -0xffda9c15, 
+    -0xffcbbce6, -0xffba5bf4, -0xffa675e8, -0xff9006f0, -0xff770aba, -0xff5b7c7e, 
+    -0xff3d56f2, -0xff1c9452, -0xfef92e59, -0xfed31e45, -0xfeaa5cd5, -0xfe7ee247, 
+    -0xfe50a657, -0xfe1fa041, -0xfdebc6c1, -0xfdb5100d, -0xfd7b71d5, -0xfd3ee149, 
+    -0xfcff5311, -0xfcbcbb49, -0xfc770d99, -0xfc2e3d15, -0xfbe23c39, -0xfb92fd29, 
+    -0xfb407141, -0xfaea8989, -0xfa913661, -0xfa3467b1, -0xf9d40cd9, -0xf9701499, 
+    -0xf9086d41, -0xf89d04a9, -0xf82dc7f1, -0xf7baa3e1, -0xf74384b1, -0xf6c85611, 
+    -0xf6490321, -0xf5c576b1, -0xf53d9b21, -0xf4b15a01, -0xf4209ce1, -0xf38b4c71, 
+    -0xf2f15171, -0xf2529411, -0xf1aefbf1, -0xf10670a1, -0xf058d941, -0xefa61cc1, 
+    -0xeeee21c1, -0xee30cec1, -0xed6e0a41, -0xeca5ba61, -0xebd7c5c1, -0xeb041241, 
+    -0xea2a8601, -0xe94b0861, -0xe8657f61, -0xe779d241, -0xe687e861, -0xe58fa9e1, 
+    -0xe490fec1, -0xe38bd101, -0xe28009c1, -0xe16d93e1, -0xe0545ba1, -0xdf344dc1, 
+    -0xde0d5881, -0xdcdf6bc1, -0xdbaa7801, -0xda6e70c1, -0xd92b4ac1, -0xd7e0fc81, 
+    -0xd68f7ec1, -0xd536cd41, -0xd3d6e5c1, -0xd26fc901, -0xd10179c1, -0xcf8bff41, 
+    -0xce0f6301, -0xcc8bb241, -0xcb00fdc1, -0xc96f5b01, -0xc7d6e141, -0xc637af41, 
+    -0xc491e4c1, -0xc2e5a801, -0xc1332401, -0xbf7a8701, -0xbdbc0681, -0xbbf7da01, 
+    -0xba2e4181, -0xb85f7f81, -0xb68bde01, -0xb4b3a981, -0xb2d73781, -0xb0f6df01, 
+    -0xaf12ff01, -0xad2bfa81, -0xab423981, -0xa9562981, -0xa7683c01, -0xa578e701, 
+    -0xa388a681, -0xa197f801, -0x9fa75e81, -0x9db75f01, -0x9bc88201, -0x99db5301, 
+    -0x97f06001, -0x96083601, -0x94236601, -0x92427f81, -0x90661481, -0x8e8eb481, 
+    -0x8cbced01, -0x8af14d81, -0x892c5f81, -0x876eab01, -0x85b8b681, -0x840b0301, 
+    -0x82660c01, -0x80ca4a01,  
 };
 
 /* Gain tables scaled by 2^16 */
diff --git a/apps/codecs/libatrac/fixp_math.h b/apps/codecs/libatrac/fixp_math.h
index 8a734f6b68..88cb5e4b66 100644
--- a/apps/codecs/libatrac/fixp_math.h
+++ b/apps/codecs/libatrac/fixp_math.h
@@ -10,27 +10,77 @@
 
 /* Fixed point math routines for use in atrac3.c */
 
-static inline int32_t fixmul16(int32_t x, int32_t y)
-{
-    int64_t temp;
-    temp = x;
-    temp *= y;
-
-    temp >>= 16;
-
-    return (int32_t)temp;
-}
-
-static inline int32_t fixmul31(int32_t x, int32_t y)
-{
-    int64_t temp;
-    temp = x;
-    temp *= y;
-
-    temp >>= 31;        //16+31-16 = 31 bits
-
-    return (int32_t)temp;
-}
+#if defined(CPU_ARM)
+    #define fixmul16(X,Y) \
+     ({ \
+        int32_t low; \
+        int32_t high; \
+        asm volatile (                   /* calculates: result = (X*Y)>>16 */ \
+           "smull  %0,%1,%2,%3 \n\t"     /* 64 = 32x32 multiply */ \
+           "mov %0, %0, lsr #16 \n\t"    /* %0 = %0 >> 16 */ \
+           "orr %0, %0, %1, lsl #16 \n\t"/* result = %0 OR (%1 << 16) */ \
+           : "=&r"(low), "=&r" (high) \
+           : "r"(X),"r"(Y)); \
+        low; \
+     })
+     
+    #define fixmul31(X,Y) \
+     ({ \
+        int32_t low; \
+        int32_t high; \
+        asm volatile (                   /* calculates: result = (X*Y)>>31 */ \
+           "smull  %0,%1,%2,%3 \n\t"     /* 64 = 32x32 multiply */ \
+           "mov %0, %0, lsr #31 \n\t"    /* %0 = %0 >> 31 */ \
+           "orr %0, %0, %1, lsl #1 \n\t" /* result = %0 OR (%1 << 1) */ \
+           : "=&r"(low), "=&r" (high) \
+           : "r"(X),"r"(Y)); \
+        low; \
+     })
+     
+    #define fixmul32(X,Y) \
+     ({ \
+        int32_t low; \
+        int32_t high; \
+        asm volatile (                   /* calculates: result = (X*Y)>>32 */ \
+           "smull  %0,%1,%2,%3 \n\t"     /* 64 = 32x32 multiply */ \
+           : "=&r"(low), "=&r" (high) \
+           : "r"(X),"r"(Y)); \
+        high; \
+     })
+#else
+    static inline int32_t fixmul16(int32_t x, int32_t y)
+    {
+        int64_t temp;
+        temp = x;
+        temp *= y;
+    
+        temp >>= 16;
+    
+        return (int32_t)temp;
+    }
+    
+    static inline int32_t fixmul31(int32_t x, int32_t y)
+    {
+        int64_t temp;
+        temp = x;
+        temp *= y;
+    
+        temp >>= 31;        //16+31-16 = 31 bits
+    
+        return (int32_t)temp;
+    }
+    
+    static inline int32_t fixmul32(int32_t x, int32_t y)
+    {
+        int64_t temp;
+        temp = x;
+        temp *= y;
+    
+        temp >>= 32;        //16+31-16 = 31 bits
+    
+        return (int32_t)temp;
+    }
+#endif
 
 static inline int32_t fixdiv16(int32_t x, int32_t y)
 {
-- 
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