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 Filename: /audio/gsm_amr/c/src/l_extract.c
35
36 Date: 09/07/2000
37
38 ------------------------------------------------------------------------------
39 REVISION HISTORY
40
41 Description: Updated template. Changed function interface to pass in a
42 pointer to overflow flag into the function instead of using a
43 global flag. Changed names of function parameters for clarity.
44 Removed inclusion of unwanted header files.
45
46 Description:
47
48 ------------------------------------------------------------------------------
49 */
50
51 /*----------------------------------------------------------------------------
52 ; INCLUDES
53 ----------------------------------------------------------------------------*/
54 #include "basic_op.h"
55
56 /*----------------------------------------------------------------------------
57 ; MACROS
58 ; [Define module specific macros here]
59 ----------------------------------------------------------------------------*/
60
61 /*----------------------------------------------------------------------------
62 ; DEFINES
63 ; [Include all pre-processor statements here. Include conditional
64 ; compile variables also.]
65 ----------------------------------------------------------------------------*/
66
67 /*----------------------------------------------------------------------------
68 ; LOCAL FUNCTION DEFINITIONS
69 ; [List function prototypes here]
70 ----------------------------------------------------------------------------*/
71
72 /*----------------------------------------------------------------------------
73 ; LOCAL VARIABLE DEFINITIONS
74 ; [Variable declaration - defined here and used outside this module]
75 ----------------------------------------------------------------------------*/
76
77
78 /*
79 ------------------------------------------------------------------------------
80 FUNCTION NAME: L_extract
81 ------------------------------------------------------------------------------
82 INPUT AND OUTPUT DEFINITIONS
83
84 Inputs:
85 L_var = 32 bit signed integer (Word32) whose value falls
86 in the range : 0x8000 0000 <= L_32 <= 0x7fff ffff.
87
88 pL_var_hi = pointer to the most significant word of L_var (Word16).
89
90 pL_var_lo = pointer to the least significant word of L_var shifted
91 to the left by 1 (Word16).
92
93 pOverflow = pointer to overflow (Flag)
94
95 Outputs:
96 pOverflow -> 1 if the 32 bit add operation resulted in overflow
97 pL_var_hi -> MS word of L_32.
98 pL_var_lo -> LS word of L_32 shifted left by 1.
99
100 Returns:
101 None
102
103 Global Variables Used:
104 None
105
106 Local Variables Needed:
107 None
108
109 ------------------------------------------------------------------------------
110 FUNCTION DESCRIPTION
111
112 This function extracts two 16-bit double precision format (DPF) numbers
113 from a 32-bit integer. The MS word of L_var will be stored in the location
114 pointed to by pL_var_hi and the shifted LS word of L_var will be stored in
115 the location pointed to by pL_var_lo.
116
117 ------------------------------------------------------------------------------
118 REQUIREMENTS
119
120 None
121
122 ------------------------------------------------------------------------------
123 REFERENCES
124
125 [1] L_extract() function in oper_32b.c, UMTS GSM AMR speech codec, R99 -
126 Version 3.2.0, March 2, 2001
127
128 ------------------------------------------------------------------------------
129 PSEUDO-CODE
130
131
132 ------------------------------------------------------------------------------
133 RESOURCES USED [optional]
134
135 When the code is written for a specific target processor the
136 the resources used should be documented below.
137
138 HEAP MEMORY USED: x bytes
139
140 STACK MEMORY USED: x bytes
141
142 CLOCK CYCLES: (cycle count equation for this function) + (variable
143 used to represent cycle count for each subroutine
144 called)
145 where: (cycle count variable) = cycle count for [subroutine
146 name]
147
148 ------------------------------------------------------------------------------
149 CAUTION [optional]
150 [State any special notes, constraints or cautions for users of this function]
151
152 ------------------------------------------------------------------------------
153 */
154
155 /*----------------------------------------------------------------------------
156 ; FUNCTION CODE
157 ----------------------------------------------------------------------------*/
L_Extract(Word32 L_var,Word16 * pL_var_hi,Word16 * pL_var_lo,Flag * pOverflow)158 void L_Extract(Word32 L_var,
159 Word16 *pL_var_hi,
160 Word16 *pL_var_lo,
161 Flag *pOverflow)
162 {
163
164 Word32 temp;
165
166 OSCL_UNUSED_ARG(pOverflow);
167
168 temp = (L_var >> 16);
169
170 *(pL_var_hi) = (Word16) temp;
171 *(pL_var_lo) = (Word16)((L_var >> 1) - (temp << 15));
172
173 return;
174 }
175