basop32.c

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/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : sub                                                     |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |    Performs the subtraction (var1+var2) with overflow control and satu-   |
 |    ration; the 16 bit result is set at +32767 when overflow occurs or at  |
 |    -32768 when underflow occurs.                                          |
 |                                                                           |
 |   Complexity weight : 1                                                   |
 |                                                                           |
 |   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 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var_out <= 0x0000 7fff.                |
 |___________________________________________________________________________|
*/
Word16 sub (Word16 var1, Word16 var2)
{
    Word16 var_out;
    Word32 L_diff;

    L_diff = (Word32) var1 - var2;
    var_out = saturate (L_diff);

#if (WMOPS)
    multiCounter[currCounter].sub++;
#endif
    return (var_out);
}


/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : abs_s                                                   |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |    Absolute value of var1; abs_s(-32768) = 32767.                         |
 |                                                                           |
 |   Complexity weight : 1                                                   |
 |                                                                           |
 |   Inputs :                                                                |
 |                                                                           |
 |    var1                                                                   |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0x0000 0000 <= var_out <= 0x0000 7fff.                |
 |___________________________________________________________________________|
*/
Word16 abs_s (Word16 var1)
{
    Word16 var_out;

    if (var1 == (Word16) MIN_16)	
    {
        var_out = MAX_16;
    }
    else
    {
        if (var1 < 0)
        {
            var_out = -var1;
        }
        else
        {
            var_out = var1;
        }
    }

#if (WMOPS)
    multiCounter[currCounter].abs_s++;
#endif
    return (var_out);
}


/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : shl                                                     |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Arithmetically shift the 16 bit input var1 left var2 positions.Zero fill|
 |   the var2 LSB of the result. If var2 is negative, arithmetically shift   |
 |   var1 right by -var2 with sign extension. Saturate the result in case of |
 |   underflows or overflows.                                                |
 |                                                                           |
 |   Complexity weight : 1                                                   |
 |                                                                           |
 |   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 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var_out <= 0x0000 7fff.                |
 |___________________________________________________________________________|
*/
Word16 shl (Word16 var1, Word16 var2)
{
    Word16 var_out;
    Word32 result;

    if (var2 < 0)
    {
        if (var2 < -16)
            var2 = -16;
        var2 = -var2;
        var_out = shr (var1, var2);

#if (WMOPS)
        multiCounter[currCounter].shr--;
#endif
    }
    else
    {
        result = (Word32) var1 *((Word32) 1 << var2);

        if ((var2 > 15 && var1 != 0) || (result != (Word32) ((Word16) result)))
        {
            Overflow = 1;
            var_out = (var1 > 0) ? MAX_16 : MIN_16;
        }
        else
        {
            var_out = extract_l (result);

#if (WMOPS)
            multiCounter[currCounter].extract_l--;
#endif
        }
    }

#if (WMOPS)
	multiCounter[currCounter].shl++;
#endif
    return (var_out);
}


/*___________________________________________________________________________
 |                                                                           |
 |   Function Name : shr                                                     |
 |                                                                           |
 |   Purpose :                                                               |
 |                                                                           |
 |   Arithmetically shift the 16 bit input var1 right var2 positions with    |
 |   sign extension. If var2 is negative, arithmetically shift var1 left by  |
 |   -var2 with sign extension. Saturate the result in case of underflows or |
 |   overflows.                                                              |
 |                                                                           |
 |   Complexity weight : 1                                                   |
 |                                                                           |
 |   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 <= var1 <= 0x0000 7fff.                   |
 |                                                                           |
 |   Outputs :                                                               |
 |                                                                           |
 |    none                                                                   |
 |                                                                           |
 |   Return Value :                                                          |
 |                                                                           |
 |    var_out                                                                |
 |             16 bit short signed integer (Word16) whose value falls in the |
 |             range : 0xffff 8000 <= var_out <= 0x0000 7fff.                |
 |___________________________________________________________________________|
*/
Word16 shr (Word16 var1, Word16 var2)
{
    Word16 var_out;

    if (var2 < 0)
    {
        if (var2 < -16)
            var2 = -16;
        var2 = -var2;
        var_out = shl (var1, var2);

#if (WMOPS)
        multiCounter[currCounter].shl--;
#endif
    }
    else
    {
        if (var2 >= 15)
        {
            var_out = (var1 < 0) ? -1 : 0;
        }
        else
        {
            if (var1 < 0)
            {
                var_out = ~((~var1) >> var2);
            }
            else
            {
                var_out = var1 >> var2;
            }
        }
    }

#if (WMOPS)
    multiCounter[currCounter].shr++;
#endif