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