| /* ------------------------------------------------------------------ |
| * 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/cor_h_x.c |
| |
| Date: 09/07/2000 |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Created a separate file for cor_h_x function. |
| |
| Description: Synchronized file with UMTS versin 3.2.0. Updated coding |
| template. |
| |
| Description: Made the following changes per comments from Phase 2/3 review: |
| 1. Modified FOR loop in the code to count down. |
| 2. Fixed typecasting issue with TI C compiler. |
| |
| Description: Added call to round() and L_shl() functions in the last FOR |
| loop to make code bit-exact. Updated copyright year. |
| |
| Description: Modified to pass pOverflow in via a pointer, rather than |
| invoking it as a global variable. |
| |
| Description: Made the following changes |
| 1. Unrolled the correlation loop and add mechanism control |
| to compute odd or even number of computations. |
| 2. Use pointer to avoid continuos addresses calculation |
| 2. Eliminated math operations that check for saturation. |
| |
| Description: Changed round function name to pv_round to avoid conflict with |
| round function in C standard library. |
| |
| Description: |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "typedef.h" |
| #include "cnst.h" |
| #include "cor_h_x.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 |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL FUNCTION REFERENCES |
| ; Declare functions defined elsewhere and referenced in this module |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES |
| ; Declare variables used in this module but defined elsewhere |
| ----------------------------------------------------------------------------*/ |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: cor_h_x |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| h = vector containing the impulse response of the weighted synthesis |
| filter; vector contents are of type Word16; vector length is |
| 2 * L_SUBFR |
| x = target signal vector; vector contents are of type Word16; vector |
| length is L_SUBFR |
| dn = vector containing the correlation between the target and the |
| impulse response; vector contents are of type Word16; vector |
| length is L_CODE |
| sf = scaling factor of type Word16 ; 2 when mode is MR122, 1 for all |
| other modes |
| |
| Outputs: |
| dn contents are the newly calculated correlation values |
| |
| pOverflow = pointer of type Flag * to overflow indicator. |
| |
| Returns: |
| None |
| |
| Global Variables Used: |
| None |
| |
| Local Variables Needed: |
| None |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function computes the correlation between the target signal (x) and the |
| impulse response (h). |
| |
| The correlation is given by: d[n] = sum_{i=n}^{L-1} x[i] h[i-n], |
| where: n=0,...,L-1 |
| |
| d[n] is normalized such that the sum of 5 maxima of d[n] corresponding to |
| each position track does not saturate. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| cor_h.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| void cor_h_x ( |
| Word16 h[], // (i): impulse response of weighted synthesis filter |
| Word16 x[], // (i): target |
| Word16 dn[], // (o): correlation between target and h[] |
| Word16 sf // (i): scaling factor: 2 for 12.2, 1 for others |
| ) |
| { |
| cor_h_x2(h, x, dn, sf, NB_TRACK, STEP); |
| } |
| |
| |
| void cor_h_x2 ( |
| Word16 h[], // (i): impulse response of weighted synthesis filter |
| Word16 x[], // (i): target |
| Word16 dn[], // (o): correlation between target and h[] |
| Word16 sf, // (i): scaling factor: 2 for 12.2, 1 for others |
| Word16 nb_track,// (i): the number of ACB tracks |
| Word16 step // (i): step size from one pulse position to the next |
| in one track |
| ) |
| { |
| Word16 i, j, k; |
| Word32 s, y32[L_CODE], max, tot; |
| |
| // first keep the result on 32 bits and find absolute maximum |
| |
| tot = 5; |
| |
| for (k = 0; k < nb_track; k++) |
| { |
| max = 0; |
| for (i = k; i < L_CODE; i += step) |
| { |
| s = 0; |
| for (j = i; j < L_CODE; j++) |
| s = L_mac (s, x[j], h[j - i]); |
| |
| y32[i] = s; |
| |
| s = L_abs (s); |
| if (L_sub (s, max) > (Word32) 0L) |
| max = s; |
| } |
| tot = L_add (tot, L_shr (max, 1)); |
| } |
| |
| j = sub (norm_l (tot), sf); |
| |
| for (i = 0; i < L_CODE; i++) |
| { |
| dn[i] = pv_round (L_shl (y32[i], j)); |
| } |
| } |
| |
| ------------------------------------------------------------------------------ |
| 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 cor_h_x( |
| Word16 h[], /* (i): impulse response of weighted synthesis filter */ |
| Word16 x[], /* (i): target */ |
| Word16 dn[], /* (o): correlation between target and h[] */ |
| Word16 sf, /* (i): scaling factor: 2 for 12.2, 1 for others */ |
| Flag *pOverflow /* (o): pointer to overflow flag */ |
| ) |
| { |
| Word16 i; |
| Word16 j; |
| Word16 k; |
| |
| Word32 s; |
| Word32 y32[L_CODE]; |
| Word32 max; |
| Word32 tot; |
| |
| Word16 *p_x; |
| Word16 *p_ptr; |
| Word32 *p_y32; |
| |
| |
| tot = 5; |
| for (k = 0; k < NB_TRACK; k++) /* NB_TRACK = 5 */ |
| { |
| max = 0; |
| for (i = k; i < L_CODE; i += STEP) /* L_CODE = 40; STEP = 5 */ |
| { |
| s = 0; |
| p_x = &x[i]; |
| p_ptr = h; |
| |
| for (j = (L_CODE - i - 1) >> 1; j != 0; j--) |
| { |
| s += ((Word32) * (p_x++) * *(p_ptr++)) << 1; |
| s += ((Word32) * (p_x++) * *(p_ptr++)) << 1; |
| } |
| |
| s += ((Word32) * (p_x++) * *(p_ptr++)) << 1; |
| |
| if (!((L_CODE - i) & 1)) /* if even number of iterations */ |
| { |
| s += ((Word32) * (p_x++) * *(p_ptr++)) << 1; |
| } |
| |
| y32[i] = s; |
| |
| if (s < 0) |
| { |
| s = -s; |
| } |
| |
| if (s > max) |
| { |
| max = s; |
| } |
| } |
| |
| tot += (max >> 1); |
| } |
| |
| |
| j = norm_l(tot) - sf; |
| |
| p_ptr = dn; |
| p_y32 = y32;; |
| |
| for (i = L_CODE >> 1; i != 0; i--) |
| { |
| s = L_shl(*(p_y32++), j, pOverflow); |
| *(p_ptr++) = (s + 0x00008000) >> 16; |
| s = L_shl(*(p_y32++), j, pOverflow); |
| *(p_ptr++) = (s + 0x00008000) >> 16; |
| } |
| |
| return; |
| } |
