l_mult.h

实现3GPP的GSM中AMR语音的CODECS。

/* ------------------------------------------------------------------
 * Copyright (C) 2008 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/include/l_mult.h

     Date: 08/11/2000

------------------------------------------------------------------------------
 REVISION HISTORY

 Description: Created separate header file for L_mult function.

 Description: Updated function prototype declaration to reflect new interface.
              A pointer to overflow flag is passed into the function. Updated
              template.

 Description: Moved _cplusplus #ifdef after Include section.

 Description: Providing support for ARM and Linux-ARM assembly instructions.

 Description:

------------------------------------------------------------------------------
 INCLUDE DESCRIPTION

 This file contains all the constant definitions and prototype definitions
 needed by the L_mult function.

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

/*----------------------------------------------------------------------------
; CONTINUE ONLY IF NOT ALREADY DEFINED
----------------------------------------------------------------------------*/
#ifndef	L_MULT_H
#define	L_MULT_H

/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include	"basicop_malloc.h"

/*--------------------------------------------------------------------------*/
#ifdef __cplusplus
extern "C"
{
#endif

    /*----------------------------------------------------------------------------
    ; MACROS
    ; Define module specific macros here
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; DEFINES
    ; Include all pre-processor statements here.
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; EXTERNAL VARIABLES REFERENCES
    ; Declare variables used in this module but defined elsewhere
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; SIMPLE TYPEDEF'S
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; ENUMERATED TYPEDEF'S
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; STRUCTURES TYPEDEF'S
    ----------------------------------------------------------------------------*/

    /*----------------------------------------------------------------------------
    ; GLOBAL FUNCTION DEFINITIONS
    ; Function Prototype declaration
    ----------------------------------------------------------------------------*/

#if defined(PV_ARM) /* Instructions for ARM Assembly on ADS*/

    __inline Word32 L_mult(Word16 var1, Word16 var2, Flag *pOverflow)
    {
        Word32 result;
        Word32 product;

        OSCL_UNUSED_ARG(pOverflow);

        __asm
        {
            SMULBB product, var1, var2
            QADD   result, product, product
        }

        return (result);
    }

#elif defined(PV_ARM_GCC) /* Instructions for ARM-linux cross-compiler*/

    __inline Word32 L_mult(Word16 var1, Word16 var2, Flag *pOverflow)
    {
        register Word32 ra = var1;
        register Word32 rb = var2;
        Word32 result;
        Word32 product;

        OSCL_UNUSED_ARG(pOverflow);

        asm volatile("smulbb %0, %1, %2"
             : "=r"(product)
                             : "r"(ra), "r"(rb)
                            );

        asm volatile("qadd %0, %1, %2"
             : "=r"(result)
                             : "r"(product), "r"(product)
                            );

        return(result);
    }

#else /* C EQUIVALENT */

    static inline Word32 L_mult(Word16 var1, Word16 var2, Flag *pOverflow)
    {
        register Word32 L_product;

        L_product = (Word32) var1 * var2;

        if (L_product != (Word32) 0x40000000L)
        {
            L_product <<= 1;          /* Multiply by 2 */
        }
        else
        {
            *pOverflow = 1;
            L_product = MAX_32;
        }

        return (L_product);
    }
#endif
    /*----------------------------------------------------------------------------
    ; END
    ----------------------------------------------------------------------------*/
#ifdef __cplusplus
}
#endif

#endif /* _L_MULT_H */