180 lines
6.2 KiB
C++
180 lines
6.2 KiB
C++
/* ------------------------------------------------------------------
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* Copyright (C) 1998-2009 PacketVideo
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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* express or implied.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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* -------------------------------------------------------------------
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*/
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/****************************************************************************************
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Portions of this file are derived from the following 3GPP standard:
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3GPP TS 26.073
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ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
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Available from http://www.3gpp.org
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(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
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Permission to distribute, modify and use this file under the standard license
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terms listed above has been obtained from the copyright holder.
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****************************************************************************************/
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/*
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Pathname: ./gsm-amr/c/src/negate.c
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------------------------------------------------------------------------------
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REVISION HISTORY
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Description: Created separate file for the negate function. Sync'ed up with
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the current template and fixed tabs.
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Description: Removed conditional code that updates WMOPS counter
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Who: Date:
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Description:
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------------------------------------------------------------------------------
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INPUT AND OUTPUT DEFINITIONS
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Inputs:
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var1 = 16 bit short signed integer (Word16) whose value falls in
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the range : 0xffff 8000 <= var1 <= 0x0000 7fff.
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Local Stores/Buffers/Pointers Needed:
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None
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Global Stores/Buffers/Pointers Needed:
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None
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Outputs:
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var1 = negated value of input (Word16)
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Pointers and Buffers Modified:
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None
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Local Stores Modified:
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None
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Global Stores Modified:
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None
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------------------------------------------------------------------------------
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FUNCTION DESCRIPTION
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This function negates var1 with saturation; saturate in the case where input
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is -32768: negate(var1) = sub(0,var1).
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------------------------------------------------------------------------------
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REQUIREMENTS
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None
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------------------------------------------------------------------------------
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REFERENCES
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[1] basicop2.c, ETS Version 2.0.0, February 8, 1999
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------------------------------------------------------------------------------
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PSEUDO-CODE
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Word16 negate (Word16 var1)
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{
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Word16 var_out;
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var_out = (var1 == MIN_16) ? MAX_16 : -var1;
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#if (WMOPS)
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multiCounter[currCounter].negate++;
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#endif
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return (var_out);
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}
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------------------------------------------------------------------------------
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RESOURCES USED
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When the code is written for a specific target processor the
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the resources used should be documented below.
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STACK USAGE: [stack count for this module] + [variable to represent
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stack usage for each subroutine called]
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where: [stack usage variable] = stack usage for [subroutine
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name] (see [filename].ext)
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DATA MEMORY USED: x words
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PROGRAM MEMORY USED: x words
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CLOCK CYCLES: [cycle count equation for this module] + [variable
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used to represent cycle count for each subroutine
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called]
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where: [cycle count variable] = cycle count for [subroutine
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name] (see [filename].ext)
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------------------------------------------------------------------------------
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*/
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/*----------------------------------------------------------------------------
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; INCLUDES
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----------------------------------------------------------------------------*/
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#include "negate.h"
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/*----------------------------------------------------------------------------
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; MACROS
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; Define module specific macros here
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; DEFINES
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; Include all pre-processor statements here. Include conditional
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; compile variables also.
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; LOCAL FUNCTION DEFINITIONS
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; Function Prototype declaration
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; LOCAL STORE/BUFFER/POINTER DEFINITIONS
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; Variable declaration - defined here and used outside this module
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; EXTERNAL FUNCTION REFERENCES
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; Declare functions defined elsewhere and referenced in this module
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
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; Declare variables used in this module but defined elsewhere
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; FUNCTION CODE
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----------------------------------------------------------------------------*/
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Word16 negate(Word16 var1)
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{
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/*----------------------------------------------------------------------------
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; Define all local variables
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; Function body here
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----------------------------------------------------------------------------*/
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var1 = (var1 == MIN_16) ? MAX_16 : -var1;
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/*----------------------------------------------------------------------------
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; Return nothing or data or data pointer
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----------------------------------------------------------------------------*/
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return (var1);
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}
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