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 ----------------------------------------------------------------------------*/ 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
