/* ------------------------------------------------------------------ * 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/convolve.c Date: 06/19/2000 ------------------------------------------------------------------------------ REVISION HISTORY Description: Optimize for speed. Update to code template. Description: Added author name and date, fixed tabs, and added missing sections. Updated Input/Output section. Description: Optimized code by calculating two convolution sums per iteration of the outer loop, thereby, decreasing outer loop count by 2. Updated input/output definitions to be the same as the assembly file (convolve.asm). Left Pseudo-code section blank. Description: Deleted semi-colon in the Pointers modified section. 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. Fixed typecasting issue with TI C compiler. 2. Modified FOR loop to count down, wherever applicable. Description: Made the following changes 1. Unrolled the correlation loop. 2. Performed 2 correlation per pass per sample to avoid recalling the same data twice. 3. Eliminated math operations that check for saturation. Description: 1. Modified loop counter, extra unrolling did speed up code Description: Replaced "int" and/or "char" with OSCL defined types. Description: Using inlines from fxp_arithmetic.h . Description: Replacing fxp_arithmetic.h with basic_op.h. Description: ------------------------------------------------------------------------------ */ /*---------------------------------------------------------------------------- ; INCLUDES ----------------------------------------------------------------------------*/ #include "typedef.h" #include "convolve.h" #include "basic_op.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: Convolve ------------------------------------------------------------------------------ INPUT AND OUTPUT DEFINITIONS Inputs: x = pointer to input vector of L elements of type Word16 h = pointer to the filter's impulse response vector of L elements of type Word16 y = pointer to the output vector of L elements of type Word16 used for storing the convolution of x and h; L = Length of the convolution; type definition is Word16 Outputs: y buffer contains the new convolution output Returns: None Global Variables Used: None Local Variables Needed: None ------------------------------------------------------------------------------ FUNCTION DESCRIPTION Perform the convolution between two vectors x[] and h[] and write the result in the vector y[]. All vectors are of length L and only the first L samples of the convolution are computed. The convolution is given by: y[n] = sum_{i=0}^{n} x[i] h[n-i], n=0,...,L-1 ------------------------------------------------------------------------------ REQUIREMENTS None ------------------------------------------------------------------------------ REFERENCES convolve.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 ------------------------------------------------------------------------------ PSEUDO-CODE void Convolve ( Word16 x[], // (i) : input vector Word16 h[], // (i) : impulse response Word16 y[], // (o) : output vector Word16 L // (i) : vector size ) { Word16 i, n; Word32 s; for (n = 0; n < L; n++) { s = 0; move32 (); for (i = 0; i <= n; i++) { s = L_mac (s, x[i], h[n - i]); } s = L_shl (s, 3); y[n] = extract_h (s); move16 (); } 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 Convolve( Word16 x[], /* (i) : input vector */ Word16 h[], /* (i) : impulse response */ Word16 y[], /* (o) : output vector */ Word16 L /* (i) : vector size */ ) { register Word16 i, n; Word32 s1, s2; for (n = 1; n < L; n = n + 2) { h = h + n; s2 = ((Word32) * (x)) * *(h--); s1 = ((Word32) * (x++)) * *(h); for (i = (n - 1) >> 1; i != 0; i--) { s2 = amrnb_fxp_mac_16_by_16bb((Word32) * (x), (Word32) * (h--), s2); s1 = amrnb_fxp_mac_16_by_16bb((Word32) * (x++), (Word32) * (h), s1); s2 = amrnb_fxp_mac_16_by_16bb((Word32) * (x), (Word32) * (h--), s2); s1 = amrnb_fxp_mac_16_by_16bb((Word32) * (x++), (Word32) * (h), s1); } s2 = amrnb_fxp_mac_16_by_16bb((Word32) * (x), (Word32) * (h), s2); *(y++) = (Word16)(s1 >> 12); *(y++) = (Word16)(s2 >> 12); x = x - n; } return; }