1/* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13 * express or implied.
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
17 */
18/****************************************************************************************
19Portions of this file are derived from the following 3GPP standard:
20
21    3GPP TS 26.073
22    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
23    Available from http://www.3gpp.org
24
25(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26Permission to distribute, modify and use this file under the standard license
27terms listed above has been obtained from the copyright holder.
28****************************************************************************************/
29/*
30------------------------------------------------------------------------------
31
32
33
34 Pathname: ./audio/gsm-amr/c/src/cor_h_x.c
35
36     Date: 09/07/2000
37
38------------------------------------------------------------------------------
39 REVISION HISTORY
40
41 Description: Created a separate file for cor_h_x function.
42
43 Description: Synchronized file with UMTS versin 3.2.0. Updated coding
44              template.
45
46 Description: Made the following changes per comments from Phase 2/3 review:
47              1. Modified FOR loop in the code to count down.
48              2. Fixed typecasting issue with TI C compiler.
49
50 Description: Added call to round() and L_shl() functions in the last FOR
51              loop to make code bit-exact. Updated copyright year.
52
53 Description: Modified to pass pOverflow in via a pointer, rather than
54 invoking it as a global variable.
55
56 Description: Made the following changes
57              1. Unrolled the correlation loop and add mechanism control
58                 to compute odd or even number of computations.
59              2. Use pointer to avoid continuos addresses calculation
60              2. Eliminated math operations that check for saturation.
61
62 Description: Changed round function name to pv_round to avoid conflict with
63              round function in C standard library.
64
65 Description:
66
67------------------------------------------------------------------------------
68*/
69
70/*----------------------------------------------------------------------------
71; INCLUDES
72----------------------------------------------------------------------------*/
73#include "typedef.h"
74#include "cnst.h"
75#include "cor_h_x.h"
76#include "basic_op.h"
77
78/*----------------------------------------------------------------------------
79; MACROS
80; Define module specific macros here
81----------------------------------------------------------------------------*/
82
83
84/*----------------------------------------------------------------------------
85; DEFINES
86; Include all pre-processor statements here. Include conditional
87; compile variables also.
88----------------------------------------------------------------------------*/
89
90/*----------------------------------------------------------------------------
91; LOCAL FUNCTION DEFINITIONS
92; Function Prototype declaration
93----------------------------------------------------------------------------*/
94
95/*----------------------------------------------------------------------------
96; LOCAL STORE/BUFFER/POINTER DEFINITIONS
97; Variable declaration - defined here and used outside this module
98----------------------------------------------------------------------------*/
99
100/*----------------------------------------------------------------------------
101; EXTERNAL FUNCTION REFERENCES
102; Declare functions defined elsewhere and referenced in this module
103----------------------------------------------------------------------------*/
104
105/*----------------------------------------------------------------------------
106; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
107; Declare variables used in this module but defined elsewhere
108----------------------------------------------------------------------------*/
109
110/*
111------------------------------------------------------------------------------
112 FUNCTION NAME: cor_h_x
113------------------------------------------------------------------------------
114 INPUT AND OUTPUT DEFINITIONS
115
116 Inputs:
117    h = vector containing the impulse response of the weighted synthesis
118        filter; vector contents are of type Word16; vector length is
119        2 * L_SUBFR
120    x = target signal vector; vector contents are of type Word16; vector
121        length is L_SUBFR
122    dn = vector containing the correlation between the target and the
123         impulse response; vector contents are of type Word16; vector
124         length is L_CODE
125    sf = scaling factor of type Word16 ; 2 when mode is MR122, 1 for all
126         other modes
127
128 Outputs:
129    dn contents are the newly calculated correlation values
130
131    pOverflow = pointer of type Flag * to overflow indicator.
132
133 Returns:
134    None
135
136 Global Variables Used:
137    None
138
139 Local Variables Needed:
140    None
141
142------------------------------------------------------------------------------
143 FUNCTION DESCRIPTION
144
145 This function computes the correlation between the target signal (x) and the
146 impulse response (h).
147
148 The correlation is given by: d[n] = sum_{i=n}^{L-1} x[i] h[i-n],
149 where: n=0,...,L-1
150
151 d[n] is normalized such that the sum of 5 maxima of d[n] corresponding to
152 each position track does not saturate.
153
154------------------------------------------------------------------------------
155 REQUIREMENTS
156
157 None
158
159------------------------------------------------------------------------------
160 REFERENCES
161
162 cor_h.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
163
164------------------------------------------------------------------------------
165 PSEUDO-CODE
166
167void cor_h_x (
168    Word16 h[],    // (i): impulse response of weighted synthesis filter
169    Word16 x[],    // (i): target
170    Word16 dn[],   // (o): correlation between target and h[]
171    Word16 sf      // (i): scaling factor: 2 for 12.2, 1 for others
172)
173{
174    cor_h_x2(h, x, dn, sf, NB_TRACK, STEP);
175}
176
177
178void cor_h_x2 (
179    Word16 h[],    // (i): impulse response of weighted synthesis filter
180    Word16 x[],    // (i): target
181    Word16 dn[],   // (o): correlation between target and h[]
182    Word16 sf,     // (i): scaling factor: 2 for 12.2, 1 for others
183    Word16 nb_track,// (i): the number of ACB tracks
184    Word16 step    // (i): step size from one pulse position to the next
185                           in one track
186)
187{
188    Word16 i, j, k;
189    Word32 s, y32[L_CODE], max, tot;
190
191    // first keep the result on 32 bits and find absolute maximum
192
193    tot = 5;
194
195    for (k = 0; k < nb_track; k++)
196    {
197        max = 0;
198        for (i = k; i < L_CODE; i += step)
199        {
200            s = 0;
201            for (j = i; j < L_CODE; j++)
202                s = L_mac (s, x[j], h[j - i]);
203
204            y32[i] = s;
205
206            s = L_abs (s);
207            if (L_sub (s, max) > (Word32) 0L)
208                max = s;
209        }
210        tot = L_add (tot, L_shr (max, 1));
211    }
212
213    j = sub (norm_l (tot), sf);
214
215    for (i = 0; i < L_CODE; i++)
216    {
217        dn[i] = pv_round (L_shl (y32[i], j));
218    }
219}
220
221------------------------------------------------------------------------------
222 RESOURCES USED [optional]
223
224 When the code is written for a specific target processor the
225 the resources used should be documented below.
226
227 HEAP MEMORY USED: x bytes
228
229 STACK MEMORY USED: x bytes
230
231 CLOCK CYCLES: (cycle count equation for this function) + (variable
232                used to represent cycle count for each subroutine
233                called)
234     where: (cycle count variable) = cycle count for [subroutine
235                                     name]
236
237------------------------------------------------------------------------------
238 CAUTION [optional]
239 [State any special notes, constraints or cautions for users of this function]
240
241------------------------------------------------------------------------------
242*/
243
244void cor_h_x(
245    Word16 h[],       /* (i): impulse response of weighted synthesis filter */
246    Word16 x[],       /* (i): target                                        */
247    Word16 dn[],      /* (o): correlation between target and h[]            */
248    Word16 sf,        /* (i): scaling factor: 2 for 12.2, 1 for others      */
249    Flag   *pOverflow /* (o): pointer to overflow flag                      */
250)
251{
252    register Word16 i;
253    register Word16 j;
254    register Word16 k;
255
256    Word32 s;
257    Word32 y32[L_CODE];
258    Word32 max;
259    Word32 tot;
260
261    Word16 *p_x;
262    Word16 *p_ptr;
263    Word32 *p_y32;
264
265
266    tot = 5;
267    for (k = 0; k < NB_TRACK; k++)              /* NB_TRACK = 5 */
268    {
269        max = 0;
270        for (i = k; i < L_CODE; i += STEP)      /* L_CODE = 40; STEP = 5 */
271        {
272            s = 0;
273            p_x = &x[i];
274            p_ptr = h;
275
276            for (j = (L_CODE - i - 1) >> 1; j != 0; j--)
277            {
278                s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
279                s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
280            }
281
282            s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
283
284            if (!((L_CODE - i) & 1))    /* if even number of iterations */
285            {
286                s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
287            }
288
289            y32[i] = s;
290
291            if (s < 0)
292            {
293                s = -s;
294            }
295
296            if (s > max)
297            {
298                max = s;
299            }
300        }
301
302        tot += (max >> 1);
303    }
304
305
306    j = norm_l(tot) - sf;
307
308    p_ptr = dn;
309    p_y32 = y32;;
310
311    for (i = L_CODE >> 1; i != 0; i--)
312    {
313        s = L_shl(*(p_y32++), j, pOverflow);
314        *(p_ptr++) = (s + 0x00008000) >> 16;
315        s = L_shl(*(p_y32++), j, pOverflow);
316        *(p_ptr++) = (s + 0x00008000) >> 16;
317    }
318
319    return;
320}
321