139 lines
3.3 KiB
C
139 lines
3.3 KiB
C
|
/*
|
||
|
|
* 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;
|
||
|
|
}
|