1a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/* ------------------------------------------------------------------ 2a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * Copyright (C) 1998-2009 PacketVideo 3a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * 4a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * Licensed under the Apache License, Version 2.0 (the "License"); 5a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * you may not use this file except in compliance with the License. 6a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * You may obtain a copy of the License at 7a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * 8a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * http://www.apache.org/licenses/LICENSE-2.0 9a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * 10a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * Unless required by applicable law or agreed to in writing, software 11a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * distributed under the License is distributed on an "AS IS" BASIS, 12a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * express or implied. 14a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * See the License for the specific language governing permissions 15a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * and limitations under the License. 16a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber * ------------------------------------------------------------------- 17a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber */ 18a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/**************************************************************************************** 19a30d40083856cb4edd225faf8b488fab156e5976Andreas HuberPortions of this file are derived from the following 3GPP standard: 20a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 21a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 3GPP TS 26.073 22a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec 23a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Available from http://www.3gpp.org 24a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 25a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC) 26a30d40083856cb4edd225faf8b488fab156e5976Andreas HuberPermission to distribute, modify and use this file under the standard license 27a30d40083856cb4edd225faf8b488fab156e5976Andreas Huberterms listed above has been obtained from the copyright holder. 28a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber****************************************************************************************/ 29a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/* 30a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 31a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Filename: /audio/gsm_amr/c/src/sub.c 32a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 33a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 34a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber REVISION HISTORY 35a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 36a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: Created separate file for the sub function. Sync'ed up with the 37a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber current template and fixed tabs. 38a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 39a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: Changed all occurrences of L_diff to diff, deleted "short" in 40a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber the definition of var1 and var2, and fixed the range values. 41a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 42a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: Changed function prototype passing in a pointer to overflow flag 43a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber instead of using global data. 44a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 45a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: Changes made per formal review comments. 46a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 1. Changed the parameter name fron "overflow" to "pOverflow" 47a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 2. Updated template 48a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 3. Updated reference section 49a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 50a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: Removed conditional code that updates WMOPS counter 51a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 52a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: 53a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 1. Modified if-else structure to save cycles by processing 54a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber the most common case faster. 55a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 56a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Who: Date: 57a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Description: 58a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 59a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 60a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber MODULE DESCRIPTION 61a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 62a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Subtraction function with overflow control 63a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 64a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 65a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber*/ 66a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 67a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/*---------------------------------------------------------------------------- 68a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; INCLUDES 69a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber----------------------------------------------------------------------------*/ 70a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber#include "basic_op.h" 71a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 72a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/*---------------------------------------------------------------------------- 73a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; MACROS 74a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; [Define module specific macros here] 75a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber----------------------------------------------------------------------------*/ 76a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 77a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/*---------------------------------------------------------------------------- 78a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; DEFINES 79a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; [Include all pre-processor statements here. Include conditional 80a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; compile variables also.] 81a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber----------------------------------------------------------------------------*/ 82a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 83a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/*---------------------------------------------------------------------------- 84a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; LOCAL FUNCTION DEFINITIONS 85a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; [List function prototypes here] 86a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber----------------------------------------------------------------------------*/ 87a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 88a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/*---------------------------------------------------------------------------- 89a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; LOCAL VARIABLE DEFINITIONS 90a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; [Variable declaration - defined here and used outside this module] 91a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber----------------------------------------------------------------------------*/ 92a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 93a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 94a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/* 95a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 96a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber FUNCTION NAME: sub 97a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 98a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber INPUT AND OUTPUT DEFINITIONS 99a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 100a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Inputs: 101a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber var1 = 16 bit short signed integer (Word16) whose value falls in 102a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber the range : 0xffff 8000 <= var1 <= 0x0000 7fff. 103a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 104a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber var2 = 16 bit short signed integer (Word16) whose value falls in 105a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber the range : 0xffff 8000 <= var2 <= 0x0000 7fff. 106a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 107a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber pOverflow = pointer to overflow (Flag) 108a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 109a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Outputs: 110a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber pOverflow -> 1 if the subtract operation resulted in overflow 111a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 112a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Returns: 113a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber diff = 16-bit limited difference between var1 and var2 (Word16) 114a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 115a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Global Variables Used: 116a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber None 117a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 118a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Local Variables Needed: 119a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber None 120a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 121a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 122a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber FUNCTION DESCRIPTION 123a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 124a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber This function performs the subtraction (var1-var2) with overflow control and 125a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber saturation; the 16 bit result is set at +32767 when overflow occurs or at 126a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber -32768 when underflow occurs. 127a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 128a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 129a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber REQUIREMENTS 130a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 131a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber None 132a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 133a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 134a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber REFERENCES 135a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 136a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber [1] sub() function in basicop2.c, UMTS GSM AMR speech codec, R99 - 137a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Version 3.2.0, March 2, 2001 138a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 139a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 140a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 141a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber PSEUDO-CODE 142a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 143a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Word16 sub (Word16 var1, Word16 var2) 144a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber { 145a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Word16 var_out; 146a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Word32 diff; 147a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 148a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber diff = (Word32) var1 - var2; 149a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 150a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber* The reference ETSI code uses a global flag for Overflow inside the function 151a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber* saturate(). In the actual implementation a pointer to Overflow flag is passed 152a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber* in as a parameter to the function 153a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 154a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber var_out = saturate (diff); 155a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 156a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber #if (WMOPS) 157a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber multiCounter[currCounter].sub++; 158a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber #endif 159a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 160a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber return (var_out); 161a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber } 162a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 163a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 164a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber RESOURCES USED [optional] 165a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 166a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber When the code is written for a specific target processor the 167a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber the resources used should be documented below. 168a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 169a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber HEAP MEMORY USED: x bytes 170a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 171a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber STACK MEMORY USED: x bytes 172a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 173a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber CLOCK CYCLES: (cycle count equation for this function) + (variable 174a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber used to represent cycle count for each subroutine 175a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber called) 176a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber where: (cycle count variable) = cycle count for [subroutine 177a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber name] 178a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 179a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 180a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber CAUTION [optional] 181a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber [State any special notes, constraints or cautions for users of this function] 182a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 183a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber------------------------------------------------------------------------------ 184a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber*/ 185a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 186a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber/*---------------------------------------------------------------------------- 187a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber; FUNCTION CODE 188a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber----------------------------------------------------------------------------*/ 189a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 190a30d40083856cb4edd225faf8b488fab156e5976Andreas HuberWord16 sub(Word16 var1, Word16 var2, Flag *pOverflow) 191a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber{ 192a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 193a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber Word32 diff; 194a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 195a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber diff = (Word32) var1 - var2; 196a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 197a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber /* Saturate result (if necessary). */ 198a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber /* Replaced function call with in-line code */ 199a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber /* to conserve MIPS, i.e., var_out = saturate (diff) */ 200a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 201a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 202a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber if ((UWord32)(diff - 0xFFFF8000L) > 0x000FFFF) 203a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber { 204a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber if (diff > (Word32) 0x0007FFFL) 205a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber { 206a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber diff = MAX_16; 207a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber } 208a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber else 209a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber { 210a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber diff = MIN_16; 211a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber } 212a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 213a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber *pOverflow = 1; 214a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber } 215a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 216a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber 217a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber return ((Word16) diff); 218a30d40083856cb4edd225faf8b488fab156e5976Andreas Huber} 219