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/* ------------------------------------------------------------------
* Copyright (C) 1998-2009 PacketVideo
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:
3GPP TS 26.073
ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
Available from http://www.3gpp.org
(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
Pathname: ./audio/gsm-amr/c/src/residu.c
------------------------------------------------------------------------------
REVISION HISTORY
Description: Updated template used to PV coding template. First attempt at
optimizing code.
Description: Deleted stores listed in the Local Stores Needed/Modified
section.
Description: Updated file per comments gathered from Phase 2/3 review.
Description: Updating to reflect variable name changes made in residu.asm
Description: Synchronized file with UMTS version 3.2.0. Updated coding
template. Removed unnecessary include files.
Description: Made the following changes per comments from Phase 2/3 review:
1. Modified FOR loops to count down.
2. Fixed typecasting issue with TI C compiler.
Description: Made the following changes
1. Unrolled the convolutional loop.
2. Performed 4 convolution per pass to avoid recalling the same
filter coefficient as many times.
2. Eliminated math operations that check for saturation.
Description: Replaced "int" and/or "char" with OSCL defined types.
Description: Changed round function name to pv_round to avoid conflict with
round function in C standard library.
Who: Date:
Description:
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "residu.h"
#include "typedef.h"
#include "cnst.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL STORE/BUFFER/POINTER DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*
------------------------------------------------------------------------------
FUNCTION NAME: Residu
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
coef_ptr = pointer to buffer containing the prediction coefficients
input_ptr = pointer to buffer containing the speech signal
input_len = filter order
residual_ptr = pointer to buffer of residual signal
Outputs:
residual_ptr buffer contains the newly calculated the residual signal
Returns:
None
Global Variables Used:
None
Local Variables Needed:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This function computes the LP residual by filtering the input speech through
the LP inverse filter A(z).
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
residu.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
Note: Input argument names were changed to be more descriptive. Shown below
are the original names. Shown below are the name changes:
a[] <--> coef_ptr[]
x[] <--> input_ptr[]
y[] <--> residual_ptr[]
lg <--> input_len
void Residu (
Word16 a[], // (i) : prediction coefficients
Word16 x[], // (i) : speech signal
Word16 y[], // (o) : residual signal
Word16 lg // (i) : size of filtering
)
{
Word16 i, j;
Word32 s;
for (i = 0; i < lg; i++)
{
s = L_mult (x[i], a[0]);
for (j = 1; j <= M; j++)
{
s = L_mac (s, a[j], x[i - j]);
}
s = L_shl (s, 3);
y[i] = pv_round (s);
}
return;
}
------------------------------------------------------------------------------
RESOURCES USED [optional]
When the code is written for a specific target processor the
the resources used should be documented below.
HEAP MEMORY USED: x bytes
STACK MEMORY USED: x bytes
CLOCK CYCLES: (cycle count equation for this function) + (variable
used to represent cycle count for each subroutine
called)
where: (cycle count variable) = cycle count for [subroutine
name]
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
void Residu(
Word16 coef_ptr[], /* (i) : prediction coefficients*/
Word16 input_ptr[], /* (i) : speech signal */
Word16 residual_ptr[], /* (o) : residual signal */
Word16 input_len /* (i) : size of filtering */
)
{
Word16 i, j;
Word32 s1;
Word32 s2;
Word32 s3;
Word32 s4;
Word16 *p_input1;
Word16 *p_input2;
Word16 *p_input3;
Word16 *p_input4;
Word16 *p_coef;
Word16 *p_residual_ptr = &residual_ptr[input_len-1];
Word16 *p_input_ptr = &input_ptr[input_len-1-M];
for (i = input_len >> 2; i != 0; i--)
{
s1 = 0x0000800L;
s2 = 0x0000800L;
s3 = 0x0000800L;
s4 = 0x0000800L;
p_coef = &coef_ptr[M];
p_input1 = p_input_ptr--;
p_input2 = p_input_ptr--;
p_input3 = p_input_ptr--;
p_input4 = p_input_ptr--;
for (j = M >> 1; j != 0; j--)
{
s1 += ((Word32) * (p_coef) * *(p_input1++));
s2 += ((Word32) * (p_coef) * *(p_input2++));
s3 += ((Word32) * (p_coef) * *(p_input3++));
s4 += ((Word32) * (p_coef--) * *(p_input4++));
s1 += ((Word32) * (p_coef) * *(p_input1++));
s2 += ((Word32) * (p_coef) * *(p_input2++));
s3 += ((Word32) * (p_coef) * *(p_input3++));
s4 += ((Word32) * (p_coef--) * *(p_input4++));
}
s1 += (((Word32) * (p_coef)) * *(p_input1));
s2 += (((Word32) * (p_coef)) * *(p_input2));
s3 += (((Word32) * (p_coef)) * *(p_input3));
s4 += (((Word32) * (p_coef)) * *(p_input4));
*(p_residual_ptr--) = (Word16)(s1 >> 12);
*(p_residual_ptr--) = (Word16)(s2 >> 12);
*(p_residual_ptr--) = (Word16)(s3 >> 12);
*(p_residual_ptr--) = (Word16)(s4 >> 12);
}
return;
}
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