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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  Pathname: ./gsm-amr/c/src/l_abs.c
31 
32 ------------------------------------------------------------------------------
33  REVISION HISTORY
34 
35  Description: Created separate file for the L_abs function. Sync'ed up
36           with the current template and fixed tabs.
37 
38  Description: Removed conditional code that updates WMOPS counter
39 
40  Who:                       Date:
41  Description:
42 
43 ------------------------------------------------------------------------------
44  INPUT AND OUTPUT DEFINITIONS
45 
46  Inputs:
47     L_var1 = 32 bit long signed integer (Word32 ) whose value falls
48              in the range : 0x8000 0000 <= L_var1 <= 0x7fff ffff.
49 
50  Local Stores/Buffers/Pointers Needed:
51     None
52 
53  Global Stores/Buffers/Pointers Needed:
54     None
55 
56  Outputs:
57     L_var1 = absolute value of input (Word32)
58 
59  Pointers and Buffers Modified:
60     None
61 
62  Local Stores Modified:
63     None
64 
65  Global Stores Modified:
66     None
67 
68 ------------------------------------------------------------------------------
69  FUNCTION DESCRIPTION
70 
71  This function calculates the absolute value of L_var1; saturate in case
72  where the input is -214783648.
73 
74 ------------------------------------------------------------------------------
75  REQUIREMENTS
76 
77  None
78 
79 ------------------------------------------------------------------------------
80  REFERENCES
81 
82  [1] basicop2.c, ETS Version 2.0.0, February 8, 1999
83 
84 ------------------------------------------------------------------------------
85  PSEUDO-CODE
86 
87 Word32 L_abs (Word32 L_var1)
88 {
89     Word32 L_var_out;
90 
91     if (L_var1 == MIN_32)
92     {
93         L_var_out = MAX_32;
94     }
95     else
96     {
97         if (L_var1 < 0)
98         {
99             L_var_out = -L_var1;
100         }
101         else
102         {
103             L_var_out = L_var1;
104         }
105     }
106 
107 #if (WMOPS)
108     multiCounter[currCounter].L_abs++;
109 #endif
110     return (L_var_out);
111 }
112 
113 
114 ------------------------------------------------------------------------------
115  RESOURCES USED
116    When the code is written for a specific target processor the
117      the resources used should be documented below.
118 
119  STACK USAGE: [stack count for this module] + [variable to represent
120           stack usage for each subroutine called]
121 
122      where: [stack usage variable] = stack usage for [subroutine
123          name] (see [filename].ext)
124 
125  DATA MEMORY USED: x words
126 
127  PROGRAM MEMORY USED: x words
128 
129  CLOCK CYCLES: [cycle count equation for this module] + [variable
130            used to represent cycle count for each subroutine
131            called]
132 
133      where: [cycle count variable] = cycle count for [subroutine
134         name] (see [filename].ext)
135 
136 ------------------------------------------------------------------------------
137 */
138 
139 
140 /*----------------------------------------------------------------------------
141 ; INCLUDES
142 ----------------------------------------------------------------------------*/
143 #include    "basic_op.h"
144 
145 /*----------------------------------------------------------------------------
146 ; MACROS
147 ; Define module specific macros here
148 ----------------------------------------------------------------------------*/
149 
150 /*----------------------------------------------------------------------------
151 ; DEFINES
152 ; Include all pre-processor statements here. Include conditional
153 ; compile variables also.
154 ----------------------------------------------------------------------------*/
155 
156 /*----------------------------------------------------------------------------
157 ; LOCAL FUNCTION DEFINITIONS
158 ; Function Prototype declaration
159 ----------------------------------------------------------------------------*/
160 
161 /*----------------------------------------------------------------------------
162 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
163 ; Variable declaration - defined here and used outside this module
164 ----------------------------------------------------------------------------*/
165 
166 /*----------------------------------------------------------------------------
167 ; EXTERNAL FUNCTION REFERENCES
168 ; Declare functions defined elsewhere and referenced in this module
169 ----------------------------------------------------------------------------*/
170 
171 /*----------------------------------------------------------------------------
172 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
173 ; Declare variables used in this module but defined elsewhere
174 ----------------------------------------------------------------------------*/
175 
176 /*----------------------------------------------------------------------------
177 ; FUNCTION CODE
178 ----------------------------------------------------------------------------*/
L_abs(Word32 L_var1)179 Word32 L_abs(Word32 L_var1)
180 {
181     /*----------------------------------------------------------------------------
182     ; Define all local variables
183     ----------------------------------------------------------------------------*/
184 
185     /*----------------------------------------------------------------------------
186     ; Function body here
187     ----------------------------------------------------------------------------*/
188 
189     Word32 y = L_var1 - (L_var1 < 0);
190     y = y ^(y >> 31);
191     return (y);
192 
193 }
194