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 26.173
22    ANSI-C code for the Adaptive Multi-Rate - Wideband (AMR-WB) speech codec
23    Available from http://www.3gpp.org
24
25(C) 2007, 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 Filename: normalize_amr_wb.cpp
35
36     Date: 12/10/2004
37
38------------------------------------------------------------------------------
39 REVISION HISTORY
40
41
42 Description:
43
44------------------------------------------------------------------------------
45 INPUT AND OUTPUT DEFINITIONS
46
47Input
48    Int32 x             32-bit integer non-zero input
49Returns
50    Int16 i             number of leading zeros on x
51
52
53------------------------------------------------------------------------------
54 FUNCTION DESCRIPTION
55
56    Returns number of leading zeros on the non-zero input
57
58------------------------------------------------------------------------------
59 REQUIREMENTS
60
61
62------------------------------------------------------------------------------
63 REFERENCES
64
65------------------------------------------------------------------------------
66 PSEUDO-CODE
67
68------------------------------------------------------------------------------
69*/
70
71
72/*----------------------------------------------------------------------------
73; INCLUDES
74----------------------------------------------------------------------------*/
75
76#include "pv_amr_wb_type_defs.h"
77#include "normalize_amr_wb.h"
78
79/*----------------------------------------------------------------------------
80; MACROS
81; Define module specific macros here
82----------------------------------------------------------------------------*/
83
84
85/*----------------------------------------------------------------------------
86; DEFINES
87; Include all pre-processor statements here. Include conditional
88; compile variables also.
89----------------------------------------------------------------------------*/
90
91/*----------------------------------------------------------------------------
92; LOCAL FUNCTION DEFINITIONS
93; Function Prototype declaration
94----------------------------------------------------------------------------*/
95
96/*----------------------------------------------------------------------------
97; LOCAL STORE/BUFFER/POINTER DEFINITIONS
98; Variable declaration - defined here and used outside this module
99----------------------------------------------------------------------------*/
100
101/*----------------------------------------------------------------------------
102; EXTERNAL FUNCTION REFERENCES
103; Declare functions defined elsewhere and referenced in this module
104----------------------------------------------------------------------------*/
105
106/*----------------------------------------------------------------------------
107; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
108; Declare variables used in this module but defined elsewhere
109----------------------------------------------------------------------------*/
110
111/*----------------------------------------------------------------------------
112; FUNCTION CODE
113----------------------------------------------------------------------------*/
114
115#if defined(PV_ARM_V5)
116#elif defined(PV_ARM_GCC_V5)
117
118/* function is inlined in header file */
119
120
121#else
122
123int16 normalize_amr_wb(int32 x)
124{
125    /*----------------------------------------------------------------------------
126    ; Define all local variables
127    ----------------------------------------------------------------------------*/
128    int16 i;
129
130
131    if (x > 0x0FFFFFFF)
132    {
133        i = 0;  /* most likely case */
134    }
135    else if (x > 0x00FFFFFF)
136    {
137        i = 3;  /* second most likely case */
138    }
139    else if (x > 0x0000FFFF)
140    {
141        i  = x > 0x000FFFFF ?  7 :  11;
142    }
143    else
144    {
145        if (x > 0x000000FF)
146        {
147            i  = x > 0x00000FFF ?  15 :  19;
148        }
149        else
150        {
151            i  = x > 0x0000000F ?  23 :  27;
152        }
153    }
154
155
156    x <<= i;
157
158    switch (x & 0x78000000)
159    {
160        case 0x08000000:
161            i += 3;
162            break;
163
164        case 0x18000000:
165        case 0x10000000:
166            i += 2;
167            break;
168        case 0x28000000:
169        case 0x20000000:
170        case 0x38000000:
171        case 0x30000000:
172            i++;
173
174        default:
175            ;
176    }
177
178    return i;
179
180}
181
182#endif
183
184