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/* ------------------------------------------------------------------
* Copyright (C) 1998-2009 PacketVideo
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:
3GPP TS 26.073
ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
Available from http://www.3gpp.org
(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
Filename: /audio/gsm_amr/c/src/l_extract.c
Date: 09/07/2000
------------------------------------------------------------------------------
REVISION HISTORY
Description: Updated template. Changed function interface to pass in a
pointer to overflow flag into the function instead of using a
global flag. Changed names of function parameters for clarity.
Removed inclusion of unwanted header files.
Description:
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "basic_op.h"
/*----------------------------------------------------------------------------
; MACROS
; [Define module specific macros here]
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; [Include all pre-processor statements here. Include conditional
; compile variables also.]
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; [List function prototypes here]
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL VARIABLE DEFINITIONS
; [Variable declaration - defined here and used outside this module]
----------------------------------------------------------------------------*/
/*
------------------------------------------------------------------------------
FUNCTION NAME: L_extract
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
L_var = 32 bit signed integer (Word32) whose value falls
in the range : 0x8000 0000 <= L_32 <= 0x7fff ffff.
pL_var_hi = pointer to the most significant word of L_var (Word16).
pL_var_lo = pointer to the least significant word of L_var shifted
to the left by 1 (Word16).
pOverflow = pointer to overflow (Flag)
Outputs:
pOverflow -> 1 if the 32 bit add operation resulted in overflow
pL_var_hi -> MS word of L_32.
pL_var_lo -> LS word of L_32 shifted left by 1.
Returns:
None
Global Variables Used:
None
Local Variables Needed:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This function extracts two 16-bit double precision format (DPF) numbers
from a 32-bit integer. The MS word of L_var will be stored in the location
pointed to by pL_var_hi and the shifted LS word of L_var will be stored in
the location pointed to by pL_var_lo.
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
[1] L_extract() function in oper_32b.c, UMTS GSM AMR speech codec, R99 -
Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
------------------------------------------------------------------------------
RESOURCES USED [optional]
When the code is written for a specific target processor the
the resources used should be documented below.
HEAP MEMORY USED: x bytes
STACK MEMORY USED: x bytes
CLOCK CYCLES: (cycle count equation for this function) + (variable
used to represent cycle count for each subroutine
called)
where: (cycle count variable) = cycle count for [subroutine
name]
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; FUNCTION CODE
----------------------------------------------------------------------------*/
void L_Extract(Word32 L_var,
Word16 *pL_var_hi,
Word16 *pL_var_lo,
Flag *pOverflow)
{
Word32 temp;
OSCL_UNUSED_ARG(pOverflow);
temp = (L_var >> 16);
*(pL_var_hi) = (Word16) temp;
*(pL_var_lo) = (Word16)((L_var >> 1) - (temp << 15));
return;
}
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