Update common_audio

Corresponds to upstream commit 524e9b043e7e86fd72353b987c9d5f6a1ebf83e1

Update notes:

 * Moved src/ to webrtc/ to easily diff against the third_party/webrtc
   in the chromium tree

 * ARM/NEON/MIPS support is not yet hooked up

 * Tests have not been copied

webrtc/common_audio/signal_processing/division_operations.c

@@ -0,0 +1,138 @@
+/*
+ *  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 implementations of the divisions
+ * WebRtcSpl_DivU32U16()
+ * WebRtcSpl_DivW32W16()
+ * WebRtcSpl_DivW32W16ResW16()
+ * WebRtcSpl_DivResultInQ31()
+ * WebRtcSpl_DivW32HiLow()
+ *
+ * The description header can be found in signal_processing_library.h
+ *
+ */
+
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+
+uint32_t WebRtcSpl_DivU32U16(uint32_t num, uint16_t den)
+{
+    // Guard against division with 0
+    if (den != 0)
+    {
+        return (uint32_t)(num / den);
+    } else
+    {
+        return (uint32_t)0xFFFFFFFF;
+    }
+}
+
+int32_t WebRtcSpl_DivW32W16(int32_t num, int16_t den)
+{
+    // Guard against division with 0
+    if (den != 0)
+    {
+        return (int32_t)(num / den);
+    } else
+    {
+        return (int32_t)0x7FFFFFFF;
+    }
+}
+
+int16_t WebRtcSpl_DivW32W16ResW16(int32_t num, int16_t den)
+{
+    // Guard against division with 0
+    if (den != 0)
+    {
+        return (int16_t)(num / den);
+    } else
+    {
+        return (int16_t)0x7FFF;
+    }
+}
+
+int32_t WebRtcSpl_DivResultInQ31(int32_t num, int32_t den)
+{
+    int32_t L_num = num;
+    int32_t L_den = den;
+    int32_t div = 0;
+    int k = 31;
+    int change_sign = 0;
+
+    if (num == 0)
+        return 0;
+
+    if (num < 0)
+    {
+        change_sign++;
+        L_num = -num;
+    }
+    if (den < 0)
+    {
+        change_sign++;
+        L_den = -den;
+    }
+    while (k--)
+    {
+        div <<= 1;
+        L_num <<= 1;
+        if (L_num >= L_den)
+        {
+            L_num -= L_den;
+            div++;
+        }
+    }
+    if (change_sign == 1)
+    {
+        div = -div;
+    }
+    return div;
+}
+
+int32_t WebRtcSpl_DivW32HiLow(int32_t num, int16_t den_hi, int16_t den_low)
+{
+    int16_t approx, tmp_hi, tmp_low, num_hi, num_low;
+    int32_t tmpW32;
+
+    approx = (int16_t)WebRtcSpl_DivW32W16((int32_t)0x1FFFFFFF, den_hi);
+    // result in Q14 (Note: 3FFFFFFF = 0.5 in Q30)
+
+    // tmpW32 = 1/den = approx * (2.0 - den * approx) (in Q30)
+    tmpW32 = (den_hi * approx << 1) + ((den_low * approx >> 15) << 1);
+    // tmpW32 = den * approx
+
+    tmpW32 = (int32_t)0x7fffffffL - tmpW32; // result in Q30 (tmpW32 = 2.0-(den*approx))
+
+    // Store tmpW32 in hi and low format
+    tmp_hi = (int16_t)(tmpW32 >> 16);
+    tmp_low = (int16_t)((tmpW32 - ((int32_t)tmp_hi << 16)) >> 1);
+
+    // tmpW32 = 1/den in Q29
+    tmpW32 = (tmp_hi * approx + (tmp_low * approx >> 15)) << 1;
+
+    // 1/den in hi and low format
+    tmp_hi = (int16_t)(tmpW32 >> 16);
+    tmp_low = (int16_t)((tmpW32 - ((int32_t)tmp_hi << 16)) >> 1);
+
+    // Store num in hi and low format
+    num_hi = (int16_t)(num >> 16);
+    num_low = (int16_t)((num - ((int32_t)num_hi << 16)) >> 1);
+
+    // num * (1/den) by 32 bit multiplication (result in Q28)
+
+    tmpW32 = num_hi * tmp_hi + (num_hi * tmp_low >> 15) +
+        (num_low * tmp_hi >> 15);
+
+    // Put result in Q31 (convert from Q28)
+    tmpW32 = WEBRTC_SPL_LSHIFT_W32(tmpW32, 3);
+
+    return tmpW32;
+}