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/norm_l.c 31 32 ------------------------------------------------------------------------------ 33 REVISION HISTORY 34 35 Description: Created separate file for the norm_l function. Sync'ed up 36 with the current template and fixed tabs. 37 38 Description: Updated module description to be the same as the equivalent 39 assembly file (norm_l.asm). 40 41 Description: Removed conditional code that updates WMOPS counter 42 43 Description: Made the following changes 44 1. Unrolled the search loop to make four comparison per 45 pass, using only four iterations of the loop and saving 46 shifts cycles 47 2. Updated header and copyright year 48 49 Description: 1. Support for ARM and Linux-ARM assembly instructions. 50 51 Who: Date: 52 Description: 53 54 ------------------------------------------------------------------------------ 55 INPUT AND OUTPUT DEFINITIONS 56 57 Inputs: 58 L_var1 = 32 bit long signed integer (Word32) whose value falls 59 in the range : 0x8000 0000 <= var1 <= 0x7fff ffff. 60 61 Local Stores/Buffers/Pointers Needed: 62 None 63 64 Global Stores/Buffers/Pointers Needed: 65 None 66 67 Outputs: 68 var_out = number of left shifts need to normalize input (Word16) 69 70 Pointers and Buffers Modified: 71 None 72 73 Local Stores Modified: 74 None 75 76 Global Stores Modified: 77 None 78 79 ------------------------------------------------------------------------------ 80 FUNCTION DESCRIPTION 81 82 This function produces the number of left shifts needed to normalize the 32 83 bit variable L_var1 for positive values on the interval with minimum of 84 0x40000000 and maximum of 0x7fffffff, and for negative values on the interval 85 with minimum of 0x80000000 and maximum of 0xc0000000. Note that when L_var1 86 is equal to zero, the output var_out is set to zero. 87 88 ------------------------------------------------------------------------------ 89 REQUIREMENTS 90 91 None 92 93 ------------------------------------------------------------------------------ 94 REFERENCES 95 96 [1] basicop2.c, ETS Version 2.0.0, February 8, 1999 97 98 ------------------------------------------------------------------------------ 99 PSEUDO-CODE 100 101 Word16 norm_l (Word32 L_var1) 102 { 103 Word16 var_out; 104 105 if (L_var1 == 0) 106 { 107 var_out = 0; 108 } 109 else 110 { 111 if (L_var1 == (Word32) 0xffffffffL) 112 { 113 var_out = 31; 114 } 115 else 116 { 117 if (L_var1 < 0) 118 { 119 L_var1 = ~L_var1; 120 } 121 for (var_out = 0; L_var1 < (Word32) 0x40000000L; var_out++) 122 { 123 L_var1 <<= 1; 124 } 125 } 126 } 127 128 #if (WMOPS) 129 multiCounter[currCounter].norm_l++; 130 #endif 131 return (var_out); 132 } 133 134 ------------------------------------------------------------------------------ 135 RESOURCES USED 136 When the code is written for a specific target processor the 137 the resources used should be documented below. 138 139 STACK USAGE: [stack count for this module] + [variable to represent 140 stack usage for each subroutine called] 141 142 where: [stack usage variable] = stack usage for [subroutine 143 name] (see [filename].ext) 144 145 DATA MEMORY USED: x words 146 147 PROGRAM MEMORY USED: x words 148 149 CLOCK CYCLES: [cycle count equation for this module] + [variable 150 used to represent cycle count for each subroutine 151 called] 152 153 where: [cycle count variable] = cycle count for [subroutine 154 name] (see [filename].ext) 155 156 ------------------------------------------------------------------------------ 157 */ 158 159 160 /*---------------------------------------------------------------------------- 161 ; INCLUDES 162 ----------------------------------------------------------------------------*/ 163 #include "basic_op.h" 164 165 /*---------------------------------------------------------------------------- 166 ; MACROS 167 ; Define module specific macros here 168 ----------------------------------------------------------------------------*/ 169 170 /*---------------------------------------------------------------------------- 171 ; DEFINES 172 ; Include all pre-processor statements here. Include conditional 173 ; compile variables also. 174 ----------------------------------------------------------------------------*/ 175 176 /*---------------------------------------------------------------------------- 177 ; LOCAL FUNCTION DEFINITIONS 178 ; Function Prototype declaration 179 ----------------------------------------------------------------------------*/ 180 181 /*---------------------------------------------------------------------------- 182 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 183 ; Variable declaration - defined here and used outside this module 184 ----------------------------------------------------------------------------*/ 185 186 /*---------------------------------------------------------------------------- 187 ; EXTERNAL FUNCTION REFERENCES 188 ; Declare functions defined elsewhere and referenced in this module 189 ----------------------------------------------------------------------------*/ 190 191 /*---------------------------------------------------------------------------- 192 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 193 ; Declare variables used in this module but defined elsewhere 194 ----------------------------------------------------------------------------*/ 195 196 /*---------------------------------------------------------------------------- 197 ; FUNCTION CODE 198 ----------------------------------------------------------------------------*/ 199 #if !( defined(PV_ARM_V5) || defined(PV_ARM_GCC_V5) ) 200 Word16 norm_l(Word32 L_var1) 201 { 202 /*---------------------------------------------------------------------------- 203 ; Define all local variables 204 ----------------------------------------------------------------------------*/ 205 Word16 var_out = 0; 206 207 /*---------------------------------------------------------------------------- 208 ; Function body here 209 ----------------------------------------------------------------------------*/ 210 211 if (L_var1) 212 { 213 214 Word32 y = L_var1 - (L_var1 < 0); 215 L_var1 = y ^(y >> 31); 216 217 218 while (!(0x40000000L & L_var1)) 219 { 220 var_out++; 221 if ((0x20000000L & L_var1)) 222 { 223 break; 224 } 225 var_out++; 226 if ((0x10000000L & L_var1)) 227 { 228 break; 229 } 230 var_out++; 231 if ((0x08000000L & L_var1)) 232 { 233 break; 234 } 235 var_out++; 236 L_var1 <<= 4; 237 } 238 } 239 240 /*---------------------------------------------------------------------------- 241 ; Return nothing or data or data pointer 242 ----------------------------------------------------------------------------*/ 243 244 245 return (var_out); 246 } 247 #endif 248
