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 /****************************************************************************************
19 Portions 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)
26 Permission to distribute, modify and use this file under the standard license
27 terms listed above has been obtained from the copyright holder.
28 ****************************************************************************************/
29 /*
30 ------------------------------------------------------------------------------
31
32
33
34 Pathname: ./audio/gsm-amr/c/src/lag_wind.c
35
36 Date: 01/31/2002
37
38 ------------------------------------------------------------------------------
39 REVISION HISTORY
40
41 Description:
42 1. Eliminated unused include files.
43 2. Replaced array addressing by pointers
44 3. Eliminated l_extract() function call
45
46 Description: Added casting to eliminate warnings
47
48 Description: Replaced "int" and/or "char" with OSCL defined types.
49
50 Description:
51
52 ------------------------------------------------------------------------------
53 */
54
55 /*----------------------------------------------------------------------------
56 ; INCLUDES
57 ----------------------------------------------------------------------------*/
58 #include "lag_wind.h"
59 #include "lag_wind_tab.h"
60 #include "basic_op.h"
61
62 /*----------------------------------------------------------------------------
63 ; MACROS
64 ; Define module specific macros here
65 ----------------------------------------------------------------------------*/
66
67
68 /*----------------------------------------------------------------------------
69 ; DEFINES
70 ; Include all pre-processor statements here. Include conditional
71 ; compile variables also.
72 ----------------------------------------------------------------------------*/
73
74
75 /*----------------------------------------------------------------------------
76 ; LOCAL FUNCTION DEFINITIONS
77 ; Function Prototype declaration
78 ----------------------------------------------------------------------------*/
79
80
81 /*----------------------------------------------------------------------------
82 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
83 ; Variable declaration - defined here and used outside this module
84 ----------------------------------------------------------------------------*/
85
86
87 /*
88 ------------------------------------------------------------------------------
89 FUNCTION NAME: lag_wind
90 ------------------------------------------------------------------------------
91 INPUT AND OUTPUT DEFINITIONS
92
93 Inputs:
94 m = LPC order of type Word16
95 r_h[] = pointer to autocorrelations (msb) of type Word16
96 r_l[] = pointer to autocorrelations (lsb) of type Word16
97 pOverflow = pointer to overflow flag
98
99 Outputs:
100 None
101
102 Returns:
103 None
104
105 Global Variables Used:
106 None.
107
108 Local Variables Needed:
109 None.
110
111 ------------------------------------------------------------------------------
112 FUNCTION DESCRIPTION
113
114 File : lag_wind.c
115 Purpose : Lag windowing of autocorrelations.
116
117 FUNCTION: Lag_window()
118
119 PURPOSE: Lag windowing of autocorrelations.
120
121 DESCRIPTION:
122 r[i] = r[i]*lag_wind[i], i=1,...,10
123
124 r[i] and lag_wind[i] are in special double precision format.
125 See "oper_32b.c" for the format.
126
127 ------------------------------------------------------------------------------
128 REQUIREMENTS
129
130 None.
131
132 ------------------------------------------------------------------------------
133 REFERENCES
134
135 lag_wind.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
136
137 ------------------------------------------------------------------------------
138 PSEUDO-CODE
139
140 Word16 i;
141 Word32 x;
142
143 for (i = 1; i <= m; i++)
144 {
145 x = Mpy_32 (r_h[i], r_l[i], lag_h[i - 1], lag_l[i - 1], pOverflow);
146 L_Extract (x, &r_h[i], &r_l[i], pOverflow);
147 }
148 return;
149
150 ------------------------------------------------------------------------------
151 RESOURCES USED [optional]
152
153 When the code is written for a specific target processor the
154 the resources used should be documented below.
155
156 HEAP MEMORY USED: x bytes
157
158 STACK MEMORY USED: x bytes
159
160 CLOCK CYCLES: (cycle count equation for this function) + (variable
161 used to represent cycle count for each subroutine
162 called)
163 where: (cycle count variable) = cycle count for [subroutine
164 name]
165
166 ------------------------------------------------------------------------------
167 CAUTION [optional]
168 [State any special notes, constraints or cautions for users of this function]
169
170 ------------------------------------------------------------------------------
171 */
Lag_window(Word16 m,Word16 r_h[],Word16 r_l[],Flag * pOverflow)172 void Lag_window(
173 Word16 m, /* (i) : LPC order */
174 Word16 r_h[], /* (i/o) : Autocorrelations (msb) */
175 Word16 r_l[], /* (i/o) : Autocorrelations (lsb) */
176 Flag *pOverflow
177 )
178 {
179 Word16 i;
180 Word32 x;
181 const Word16 *p_lag_h = &lag_h[0];
182 const Word16 *p_lag_l = &lag_l[0];
183 Word16 *p_r_h = &r_h[1];
184 Word16 *p_r_l = &r_l[1];
185
186 for (i = m; i != 0 ; i--)
187 {
188 x = Mpy_32(*(p_r_h), *(p_r_l), *(p_lag_h++), *(p_lag_l++), pOverflow);
189 *(p_r_h) = (Word16)(x >> 16);
190 *(p_r_l++) = (x >> 1) - (*(p_r_h++) << 15);
191 }
192
193 return;
194 }
195
196