basic_op_c_equivalent.h

实现3GPP的GSM中AMR语音的CODECS。

        {
            L_product <<= 1;          /* Multiply by 2 */
        }
        else
        {
            *pOverflow = 1;
            L_product = MAX_32;
        }

        return (L_product);
    }


    /*
    ------------------------------------------------------------------------------
     FUNCTION NAME: L_msu
    ------------------------------------------------------------------------------
     INPUT AND OUTPUT DEFINITIONS

     Inputs:
        L_var3 = 32 bit long signed integer (Word32) whose value falls
                 in the range : 0x8000 0000 <= L_var3 <= 0x7fff ffff.

        var1 = 16 bit short signed integer (Word16) whose value falls in
               the range : 0xffff 8000 <= var1 <= 0x0000 7fff.
        var2 = 16 bit short signed integer (Word16) whose value falls in
               the range : 0xffff 8000 <= var2 <= 0x0000 7fff.

        pOverflow = pointer to overflow (Flag)

     Outputs:
        pOverflow -> 1 if the 32 bit operation resulted in overflow

     Returns:
        result = 32-bit result of L_var3 - (var1 * var2)
    */

    static inline Word32 L_msu(Word32 L_var3, Word16 var1, Word16 var2, Flag *pOverflow)
    {
        Word32 result;

        result = L_mult(var1, var2, pOverflow);
        result = L_sub(L_var3, result, pOverflow);

        return (result);
    }

    /*
    ------------------------------------------------------------------------------
     FUNCTION NAME: Mpy_32
    ------------------------------------------------------------------------------
     INPUT AND OUTPUT DEFINITIONS

     Inputs:
        L_var1_hi = most significant word of first input (Word16).
        L_var1_lo = least significant word of first input (Word16).
        L_var2_hi = most significant word of second input (Word16).
        L_var2_lo = least significant word of second input (Word16).

        pOverflow = pointer to overflow (Flag)

     Outputs:
        pOverflow -> 1 if the 32 bit multiply operation resulted in overflow

     Returns:
        L_product = 32-bit product of L_var1 and L_var2 (Word32)
    */
    __inline Word32 Mpy_32(Word16 L_var1_hi,
                           Word16 L_var1_lo,
                           Word16 L_var2_hi,
                           Word16 L_var2_lo,
                           Flag   *pOverflow)
    {
        Word32 L_product;
        Word32 L_sum;
        Word32 product32;

        OSCL_UNUSED_ARG(pOverflow);
        L_product = (Word32) L_var1_hi * L_var2_hi;

        if (L_product != (Word32) 0x40000000L)
        {
            L_product <<= 1;
        }
        else
        {
            L_product = MAX_32;
        }

        /* result = mult (L_var1_hi, L_var2_lo, pOverflow); */
        product32 = ((Word32) L_var1_hi * L_var2_lo) >> 15;

        /* L_product = L_mac (L_product, result, 1, pOverflow); */
        L_sum = L_product + (product32 << 1);

        if ((L_product ^ product32) > 0)
        {
            if ((L_sum ^ L_product) < 0)
            {
                L_sum = (L_product < 0) ? MIN_32 : MAX_32;
            }
        }

        L_product = L_sum;

        /* result = mult (L_var1_lo, L_var2_hi, pOverflow); */
        product32 = ((Word32) L_var1_lo * L_var2_hi) >> 15;

        /* L_product = L_mac (L_product, result, 1, pOverflow); */
        L_sum = L_product + (product32 << 1);

        if ((L_product ^ product32) > 0)
        {
            if ((L_sum ^ L_product) < 0)
            {
                L_sum = (L_product < 0) ? MIN_32 : MAX_32;
            }
        }
        return (L_sum);
    }

    /*
    ------------------------------------------------------------------------------
     FUNCTION NAME: Mpy_32_16
    ------------------------------------------------------------------------------
     INPUT AND OUTPUT DEFINITIONS

     Inputs:
        L_var1_hi = most significant 16 bits of 32-bit input (Word16).
        L_var1_lo = least significant 16 bits of 32-bit input (Word16).
        var2  = 16-bit signed integer (Word16).

        pOverflow = pointer to overflow (Flag)

     Outputs:
        pOverflow -> 1 if the 32 bit product operation resulted in overflow

     Returns:
        product = 32-bit product of the 32-bit L_var1 and 16-bit var1 (Word32)
    */

    __inline Word32 Mpy_32_16(Word16 L_var1_hi,
                              Word16 L_var1_lo,
                              Word16 var2,
                              Flag *pOverflow)
    {

        Word32 L_product;
        Word32 L_sum;
        Word32 result;
        L_product = (Word32) L_var1_hi * var2;

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

        result = ((Word32)L_var1_lo * var2) >> 15;

        L_sum  =  L_product + (result << 1);

        if ((L_product ^ result) > 0)
        {
            if ((L_sum ^ L_product) < 0)
            {
                L_sum = (L_product < 0) ? MIN_32 : MAX_32;
                *pOverflow = 1;
            }
        }
        return (L_sum);

    }

    /*
    ------------------------------------------------------------------------------
     FUNCTION NAME: mult
    ------------------------------------------------------------------------------
     INPUT AND OUTPUT DEFINITIONS

     Inputs:
    	var1 = 16 bit short signed integer (Word16) whose value falls in
    	       the range : 0xffff 8000 <= var1 <= 0x0000 7fff.

    	var2 = 16 bit short signed integer (Word16) whose value falls in
    	       the range : 0xffff 8000 <= var2 <= 0x0000 7fff.

    	pOverflow = pointer to overflow (Flag)

     Outputs:
    	pOverflow -> 1 if the add operation resulted in overflow

     Returns:
    	product = 16-bit limited product of var1 and var2 (Word16)
    */
    static inline Word16 mult(Word16 var1, Word16 var2, Flag *pOverflow)
    {
        register Word32 product;

        product = ((Word32) var1 * var2) >> 15;

        /* Saturate result (if necessary). */
        /* var1 * var2 >0x00007fff is the only case */
        /* that saturation occurs. */

        if (product > 0x00007fffL)
        {
            *pOverflow = 1;
            product = (Word32) MAX_16;
        }


        /* Return the product as a 16 bit value by type casting Word32 to Word16 */

        return ((Word16) product);
    }


    static inline Word32 amrnb_fxp_mac_16_by_16bb(Word32 L_var1, Word32 L_var2, Word32 L_var3)
    {
        Word32 result;

        result = L_var3 + L_var1 * L_var2;

        return result;
    }

    static inline Word32 amrnb_fxp_msu_16_by_16bb(Word32 L_var1, Word32 L_var2, Word32 L_var3)
    {
        Word32 result;

        result = L_var3 - L_var1 * L_var2;

        return result;
    }


    /*----------------------------------------------------------------------------
    ; END
    ----------------------------------------------------------------------------*/
#ifdef __cplusplus
}
#endif

#endif /* BASIC_OP_C_EQUIVALENT_H */